Terminal apparatus for transmitting data using uplink grants

ABSTRACT

To provide a base station apparatus, a terminal apparatus, and a communication method capable of ensuring high reliability and low latency of URLLC. There are included a receiver configured to detect first and second DCI formats and RRC information, and a transmitter capable of data transmission based on any of a first uplink grant to be available via activation by using a radio resource periodicity included in the RRC information and the first DCI format, a second uplink grant to be available via activation by using the radio resource periodicity included in the RRC information and the second DCI format, and a third uplink grant to be available after detection of the second DCI format, wherein multiple DCI formats are detected, the transmitter performs an override, in a case that the third uplink grant overlaps in a time domain with the second uplink grant, and performs an override, in a case that the first uplink grant overlaps in a time domain with the third uplink grant.

TECHNICAL FIELD

The present invention relates to a terminal apparatus. This application claims priority based on JP 2018-073226 filed on Apr. 5, 2018, the contents of which are incorporated herein by reference.

BACKGROUND ART

In recent years, 5th Generation (5G) mobile telecommunication systems have been focused on, and a communication technology is expected to be specified, the technology establishing MTC mainly based on a large number of terminal apparatuses (Massive Machine Type Communications; mMTC), Ultra-reliable and low latency communications (URLLC), and enhanced Mobile BroadBand (eMBB). The 3rd Generation Partnership Project (3GPP) has been studying New Radio (NR) as a 5G communication technique and discussing NR Multiple Access (MA).

In 5G, implementation of Internet of Things (IoT) is expected that allows connection of various types of equipment not previously connected to a network, and implementation of mMTC is an important issue. In 3GPP, a Machine-to-Machine (M2M) communication technology has already been standardized as Machine Type Communication (MTC) that accommodates terminal apparatuses transmitting and/or receiving small size data (NPL 1). Furthermore, in order to support data transmission at a low rate in a narrow band, standardization of Narrow Band-IoT (NB-IoT) has been conducted (NPL 2). 5G is expected to accommodate more terminals than the above-described standards and to accommodate IoT equipment requiring ultra-reliable and low-latency communications.

On the other hand, in communication systems such as Long Term Evolution (LTE) and LTE-Advanced (LTE-A) which are specified by the 3GPP, terminal apparatuses (User Equipment (UE)) use a Random Access Procedure, a Scheduling Request (SR), and the like, to request a radio resource for transmitting uplink data to a base station apparatus (also referred to as a Base Station (BS) or an evolved Node B (eNB)). The base station apparatus provides uplink grant (UL Grant) to each terminal apparatus based on an SR. In a case that the terminal apparatus receives an UL Grant as control information from the base station apparatus, the terminal apparatus transmits uplink data using a prescribed radio resource (referred to as Scheduled access, grant-based access, or transmission by dynamic scheduling, and hereinafter referred to as scheduled access), based on uplink transmission parameters included in the UL Grant. In this manner, the base station apparatus controls all uplink data transmissions (the base station apparatus knows radio resources for uplink data transmitted by each terminal apparatus). In the scheduled access, the base station apparatus can establish Orthogonal Multiple Access (OMA) by controlling uplink radio resources.

5G mMTC includes a problem in that the use of the scheduled access increases the amount of control information. URLLC includes a problem in that the use of the scheduled access increases delay. Use of grant free access (also referred to as grant less access, Contention-based access, Autonomous access, Resource allocation for uplink transmission without grant, type 1 configured grant transmission, or the like, and hereinafter referred to as grant free access) and semi-persistent scheduling (SPS, also referred to as Type 2 configured grant transmission, or the like) is under study. In the grant free access, the terminal apparatus transmits data without performing random access procedure or SR transmission and without performing UL Grant reception, or the like (NPL 3). In the grant free access, increased overhead associated with control information can be suppressed even in a case that a large number of devices transmit small size data. Furthermore, in the grant free access, no UL Grant reception or the like is performed, and thus, the time from generation to transmission of transmission data can be shortened. In the SPS, some of the transmission parameters are notified by way of higher-layer control information, and transmission parameters not notified by the higher layer and an UL Grant for activation indicating allowance of use of a periodic resource are notified to enable the data transmission.

On the other hand, in a downlink, a resource allocated for data transmission in eMBB can be used for data transmission in URLLC. The base station apparatus notifies a destination UE in the downlink eMBB of Pre-emption control information, and uses a pre-empted resource for the downlink URLLC data transmission. On the other hand, the terminal apparatus that detects the Pre-emption control information for a resource scheduled for downlink data reception determines that there is no downlink data addressed to the terminal apparatus itself in the resource specified by the Pre-emption. Multiplex of eMBB and URLLC data between different terminal apparatuses in the uplink is also under study. In addition, multiplex of eMBB and URLLC data in a case that one terminal apparatus has traffic of eMBB and URLLC is also under study.

CITATION LIST Non Patent Literature

NPL 1: 3GPP, TR36.888 V12.0.0, “Study on provision of low-cost Machine-Type Communications (MTC) User Equipments (UEs) based on LTE,” June 2013

NPL 2: 3GPP, TR45.820 V13.0.0, “Cellular system support for ultra-low complexity and low throughput Internet of Things (CIoT),” August 2015

NPL 3: 3GPP, TS38.214 V2.0.0, “Physical layer procedures for data (Release 15),” December 2017

SUMMARY OF INVENTION Technical Problem

The grant free access or the SPS is assumed to be used for the URLLC data transmission, and the scheduled access is assumed to be used for the eMBB data transmission. However, in a case that a grant free access or SPS resource and a scheduled access resource overlap in a time domain (overlap in at least some of the OFDM symbols), the scheduled access is used. In this case, there is a problem in that the terminal apparatus transmits eMBB data of which delay time requirement is relatively less strict than that of the URLLC data transmission in which a low latency is required.

An aspect of the present invention has been made in view of such circumstances, and an object thereof is to provide a base station apparatus, a terminal apparatus, and a communication method capable of implementing data transmission based on a data transmission priority depending on a delay time requirement.

Solution to Problem

To address the above-mentioned drawbacks, a base station apparatus, a terminal apparatus, and a communication method according to an aspect of the present invention are configured as follows.

(1) An aspect of the present invention is a terminal apparatus for communicating with a base station apparatus, the terminal apparatus including a receiver configured to detect a first Downlink Control Information (DCI) format, a second DCI format, and Radio Resource Control (RRC) information, and a transmitter capable of data transmission based on any of a first uplink grant which is a configured uplink grant to be available after activation of a periodic radio resource by using a radio resource periodicity included in the RRC information and the first DCI format, a second uplink grant which is a configured uplink grant to be available after activation of the periodic radio resource by using the radio resource periodicity included in the RRC information and the second DCI format, and a third uplink grant using an uplink grant addressed to a Cell-Radio Network Temporary Identifier (C-RNTI) to be available after detection of allocation information of an aperiodic radio resource included in the second DCI format, wherein the receiver detects at least two of the first DCI format for the first uplink grant, the second DCI format for the second uplink grant, and the second DCI format for the third uplink grant, and the transmitter overrides, in a case that the uplink grant addressed to the C-RNTI of the third uplink grant overlaps in a time domain with the configured uplink grant of the second uplink grant, the configured uplink grant of the second uplink grant, and overrides, in a case that the configured uplink grant of the first uplink grant overlaps in a time domain with the uplink grant addressed to the C-RNTI of the third uplink grant, the uplink grant addressed to the C-RNTI of the third uplink grant.

(2) In an aspect of the present invention, data transmission of a fourth uplink grant is enabled, the fourth uplink grant using an uplink grant addressed to a C-RNTI to be available after detection of allocation information of an aperiodic radio resource included in the first DCI format, the receiver detects the first DCI format for the first uplink grant and the first DCI format for the fourth uplink grant, and the transmitter overrides, in a case that the uplink grant addressed to the C-RNTI of the fourth uplink grant overlaps in a time domain with the configured uplink grant of the first uplink grant, the configured uplink grant of the first uplink grant.

(3) In an aspect of the present invention, the transmitter is capable of data transmission of a fifth uplink grant which is a configured uplink grant with the RRC information including allocation information of a radio resource for data transmission, without receiving the first DCI format and the second DCI format, and the transmitter determines, in a case that the uplink grant addressed to the C-RNTI of the third uplink grant overlaps in a time domain with the configured uplink grant of the fifth uplink grant, which of the third uplink grant and the fifth uplink grant is to be used at least in an overlapping Orthogonal Frequency Division Multiplexing (OFDM) symbol, based on at least one piece of information among resource allocation in the time domain, a radio resource periodicity, and an offset in the time domain, each of which is included in the RRC information for the fifth uplink grant.

(4) In an aspect of the present invention, the configured uplink grant of the first uplink grant overlapping in a time domain with the uplink grant addressed to the C-RNTI of the third uplink grant corresponds to OFDM symbols to be used for data transmission based on the first uplink grant and OFDM symbols to be used for data transmission based on the third uplink grant being at least partially overlapping with each other.

(5) In an aspect of the present invention, the total number of bits in a field included in the first DCI format is smaller than the number of bits in the second DCI format.

Advantageous Effects of Invention

According to one or more aspects of the present invention, high reliable data transmission can be achieved.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating an example of a communication system according to a first embodiment.

FIG. 2 is a diagram illustrating an example of a radio frame structure for the communication system according to the first embodiment.

FIG. 3 is a schematic block diagram illustrating a configuration of a base station apparatus 10 according to the first embodiment.

FIG. 4 is a diagram illustrating an example of a signal detection unit according to the first embodiment.

FIG. 5 is a schematic block diagram illustrating a configuration of a terminal apparatus 20 according to the first embodiment.

FIG. 6 is a diagram illustrating an example of the signal detection unit according to the first embodiment.

FIG. 7 is a diagram illustrating an example of a known notification of an uplink grant.

FIG. 8 is a diagram illustrating an example of a notification of an uplink grant according to the first embodiment.

FIG. 9 is a diagram illustrating an example of a notification of an uplink grant according to a third embodiment.

DESCRIPTION OF EMBODIMENTS

A communication system according to the present embodiments includes a base station apparatus (also referred to as a cell, a small cell, a pico cell, a serving cell, a component carrier, an eNodeB (eNB), a Home eNodeB, a Low Power Node, a Remote Radio Head, a gNodeB (gNB), a control station, a Bandwidth Part (BWP), or a Supplementary Uplink (SUL)), and a terminal apparatus (also referred to as a terminal, a mobile terminal, a mobile station, or User Equipment (UE)). In the communication system, in case of a downlink, the base station apparatus serves as a transmitting apparatus (a transmission point, a transmit antenna group, or a transmit antenna port group), and the terminal apparatus serves as a receiving apparatus (a reception point, a reception terminal, a receive antenna group, or a receive antenna port group). In a case of an uplink, the base station apparatus serves as a receiving apparatus, and the terminal apparatus serves as a transmitting apparatus. The communication system is also applicable to Device-to-Device (D2D) communication. In this case, the terminal apparatus serves both as a transmitting apparatus and as a receiving apparatus.

The communication system is not limited to data communication between the terminal apparatus and the base station apparatus, the communication involving human beings, but is also applicable to a form of data communication requiring no human intervention, such as Machine Type Communication (MTC), Machine-to-Machine (M2M) Communication, communication for Internet of Things (IoT), or Narrow Band-IoT (NB-IoT) (hereinafter referred to as MTC). In this case, the terminal apparatus serves as an MTC terminal. The communication system can use, in the uplink and the downlink, a multi-carrier transmission scheme such as Discrete Fourier Transform Spread-Orthogonal Frequency Division Multiplexing (DFTS-OFDM, also referred to as Single Carrier-Frequency Division Multiple Access (SC-FDMA)) and Cyclic Prefix-Orthogonal Frequency Division Multiplexing (CP-OFDM). The communication system can also use Filter Bank Multi Carrier (FBMC), Filtered-OFDM (f-OFDM) to which a filter is applied, Universal Filtered-OFDM (UF-OFDM), or Windowing-OFDM (W-OFDM), a transmission scheme using a sparse code (Sparse Code Multiple Access (SCMA)), or the like. Furthermore, the communication system may apply DFT precoding and use a signal waveform for which the filter described above is used. Furthermore, the communication system may apply code spreading, interleaving, the sparse code, and the like in the above-described transmission scheme. Note that, in the description below, at least one of the DFTS-OFDM transmission and the CP-OFDM transmission is used in the uplink, whereas the CP-OFDM transmission is used in the downlink, but that the present embodiments are not limited to this configuration and any other transmission scheme is applicable.

The base station apparatus and the terminal apparatus according to the present embodiments can communicate in a frequency band for which an approval of use (license) has been obtained from the government of a country or region where a radio operator provides services, that is, a so-called licensed band, and/or in a frequency band for which no approval (license) from the government of the country or region is required, that is, a so-called unlicensed band. In the unlicensed band, communication may be based on carrier sense (e.g., a listen before talk scheme).

According to the present embodiments, “X/Y” includes the meaning of “X or Y”. According to the present embodiments, “X/Y” includes the meaning of “X and Y”. According to the present embodiments, “X/Y” includes the meaning of “X and/or Y”.

First Embodiment

FIG. 1 is a diagram illustrating an example of a configuration of a communication system according to the present embodiment. The communication system according to the present embodiment includes a base station apparatus 10 and terminal apparatuses 20-1 to 20-n 1 (n1 is a number of terminal apparatuses connected to the base station apparatus 10). The terminal apparatuses 20-1 and 20-n 1 are also collectively referred to as terminal apparatuses 20. Coverage 10 a is a range (a communication area) in which the base station apparatus 10 can connect to the terminal apparatus 20 (coverage 10 a is also referred to as a cell).

In FIG. 1, radio communication of an uplink r30 includes at least the following uplink physical channels. The uplink physical channels are used for transmitting information output from a higher layer.

-   -   Physical Uplink Control Channel (PUCCH)     -   Physical Uplink Shared Channel (PUSCH)     -   Physical Random Access Channel (PRACH)

The PUCCH is a physical channel that is used to transmit Uplink Control Information (UCI). The uplink control information includes a positive acknowledgement (ACK)/Negative acknowledgement (NACK) in response to downlink data (a Downlink transport block, a Medium Access Control Protocol Data Unit (MAC PDU), a Downlink-Shared Channel (DL-SCH), and a Physical Downlink Shared Channel (PDSCH). The ACK/NACK is also referred to as a Hybrid Automatic Repeat request ACKnowledgement (HARQ-ACK), a HARQ feedback, a HARQ response, or a signal indicating HARQ control information or a delivery confirmation.

The uplink control information includes a Scheduling Request (SR) used to request a PUSCH (Uplink-Shared Channel (UL-SCH)) resource for initial transmission. The scheduling request includes a positive scheduling request or a negative scheduling request. The positive scheduling request indicates that a UL-SCH resource for initial transmission is requested. The negative scheduling request indicates that the UL-SCH resource for the initial transmission is not requested.

The uplink control information includes downlink Channel State Information (CSI). The downlink channel state information includes a Rank Indicator (RI) indicating a preferable spatial multiplexing order (the number of layers), a Precoding Matrix Indicator (PMI) indicating a preferable precoder, a Channel Quality Indicator (CQI) designating a preferable transmission rate, and the like. The PMI indicates a codebook determined by the terminal apparatus. The codebook is related to precoding of the physical downlink shared channel. The CQI can use an index (CQI index) indicative of a preferable modulation scheme (for example, QPSK, 16QAM, 64QAM, 256QAM, or the like), a preferable coding rate, and a preferable frequency utilization efficiency in a prescribed band. The terminal apparatus selects, from the CQI table, a CQI index considered to allow a transport block on the PDSCH to be received within a prescribed block error probability (for example, an error rate of 0.1). Here, the terminal apparatus may have multiple prescribed error probabilities (error rates) for transport blocks. For example, an error rate of eMBB data may be targeted at 0.1 and an error rate for URLLC may be targeted at 0.00001, 0.001, or the like. The terminal apparatus may perform CSI feedback for each target error rate (transport block error rate) configured by the higher layer (e.g., setup through RRC signaling from the base station), or may perform CSI feedback for a target error rate of multiple target error rates configured by the higher layer. Note that the CSI may be calculated using an error rate not for eMBB (e.g. 0.1) based on not whether the error rate is configured through RRC signaling but whether a CQI table not for eMBB (that is, transmissions where the BLER does not exceed 0.1) is selected.

PUCCH formats 0 to 4 are defined for the PUCCH, and PUCCH formats 0 and 2 are transmitted in 1 to 2 OFDM symbols and PUCCH formats 1, 3, and 4 are transmitted in 4 to 14 OFDM symbols. The PUCCH formats 0 and 1 are used for up to 2-bit notification, and can notify only the HARQ-ACK or simultaneously the HARQ-ACK and the SR. The PUCCH formats 1, 3, and 4 are used for more than 2-bit notification, and can simultaneously notify the ARQ-ACK, the SR, and the CSI. The number of OFDM symbols used for PUCCH transmission is configured by a higher layer (e.g., setup through RRC signaling), and the use of any PUCCH format depends on whether there is SR transmission or CSI transmission at the timing at which the PUCCH is transmitted (slot, OFDM symbol).

The PUSCH is a physical channel that is used to transmit uplink data (Uplink Transport Block, Uplink-Shared Channel (UL-SCH)). The PUSCH may be used to transmit the HARQ-ACK in response to the downlink data and/or the channel state information along with the uplink data. The PUSCH may be used to transmit only the channel state information. The PUSCH may be used to transmit only the HARQ-ACK and the channel state information.

The PUSCH is used to transmit radio resource control (Radio Resource Control (RRC)) signaling. The RRC signaling is also referred to as an RRC message/RRC layer information/an RRC layer signal/an RRC layer parameter/an RRC information element. The RRC signaling is information/signal processed in a radio resource control layer. The RRC signaling transmitted from the base station apparatus may be signaling common to multiple terminal apparatuses in a cell. The RRC signaling transmitted from the base station apparatus may be signaling dedicated to a certain terminal apparatus (also referred to as dedicated signaling). In other words, user equipment-specific (UE-specific) information may be transmitted through signaling dedicated to the certain terminal apparatus. The RRC message can include a UE Capability of the terminal apparatus. The UE Capability is information indicating a function supported by the terminal apparatus.

The PUSCH is used to transmit a Medium Access Control Element (MAC CE). The MAC CE is information/signal processed (transmitted) in a Medium Access Control layer. For example, a Power Headroom (PH) may be included in the MAC CE and may be reported via the physical uplink shared channel. In other words, a MAC CE field is used to indicate a level of the power headroom. The uplink data can include the RRC message and the MAC CE. The RRC signaling and/or the MAC CE is also referred to as a higher layer signal (higher layer signaling). The RRC signaling and/or the MAC CE are included in a transport block.

The PUSCH may be used for data transmission of dynamic scheduling for performing uplink data transmission on a specified radio resource (allocation of an aperiodic radio resource), based on uplink transmission parameters (e.g., time-domain resource allocation, frequency-domain resource allocation, and the like) included in the DCI format. The PUSCH may be used for Semi-Persistent scheduling (SPS) Type 2 (Configured uplink grant type 2) in which data transmission using a periodic radio resource is allowed, by, through the RRC, receiving the TransformPrecoder (precoder), nrofHARQ (the number of HARQ processes), and repK-RV (a redundancy version pattern in repetitive transmission of the same data), and thereafter, receiving DCI format 0_0/0_1 with CRC scrambled with CS-RNTI, and further receiving activation control information with the received DCI format 0_0/0_1 having a prescribed field configured with Validation. Here, the most significant bit of a MCS, a NDI, a HARQ process number, and the like may be used as a field used for the Validation. Furthermore, the PUSCH may be used for SPS Type 1 in which periodic data transmission is allowed by, through the RRC, receiving rrcConfiguredUplinkGrant in addition to the SPS Type 2 information. The rrcConfiguredUplinkGrant information may include the time-domain resource allocation, a time-domain offset, the frequency-domain resource allocation, a DMRS configuration, and the number of repetitive transmissions of the same data (repK). In a case that the SPS Type 1 and the SPS Type 2 are configured in the same serving cell (in the component carrier), the SPS Type 1 may be prioritized. In a case that an uplink grant for the SPS Type 1 and an uplink grant for the dynamic scheduling overlap in the time domain in the same serving cell, the uplink grant for the dynamic scheduling may override (that is, the dynamic scheduling only is used and the uplink grant for the SPS Type 1 is not used). The multiple uplink grants overlapping in the time domain may refer to at least some of the OFDM symbols overlapping, or portions of the times in the OFDM symbols overlapping because an OFDM symbol length differs in a case that a subcarrier spacing (SCS) is different. The SPS Type 1 configuration can be configured for the Scell that is not activated through the RRC, and the uplink grant for the SPS Type 1 may be validated after the Scell configured with the SPS Type 1 is activated.

The PRACH is used to transmit a preamble used for random access. The PRACH is used for indicating the initial connection establishment procedure, the handover procedure, the connection re-establishment procedure, synchronization (timing adjustment) for uplink transmission, and the request for the PUSCH (UL-SCH) resource.

In the uplink radio communication, an Uplink Reference Signal (UL RS) is used as an uplink physical signal. The uplink reference signal includes a Demodulation Reference Signal (DMRS) and a Sounding Reference Signal (SRS). The DMRS is associated with transmission of the physical uplink-shared channel/physical uplink control channel. For example, the base station apparatus 10 uses the demodulation reference signal to perform channel estimation/channel compensation in a case of demodulating the physical uplink-shared channel/the physical uplink control channel. For an uplink DMRS, the maximum number of OFDM symbols for front-loaded DMRS and a configuration for the DMRS symbol addition (DMRS-add-pos) are specified by the base station apparatus through the RRC. In a case that the front-loaded DMRS is in 1 OFDM symbol (single symbol DMRS), a frequency domain location, cyclic shift values in the frequency domain, and how different frequency domain locations are used in the OFDM symbol including the DMRS are specified in the DCI, and in a case that the front-loaded DMRS is in 2 OFDM symbols (double symbol DMRS), a configuration for a time spread of a length 2 is specified in the DCI in addition to the above.

The Sounding Reference Signal (SRS) is not associated with the transmission of the physical uplink shared channel/physical uplink control channel. In other words, with or without uplink data transmission, the terminal apparatus transmits periodically or aperiodically the SRS. In the periodic SRS, the terminal apparatus transmits the SRS based on parameters notified through higher layer signaling (e.g., RRC) from the base station apparatus. On the other hand, in the aperiodic SRS, the terminal apparatus transmits the SRS based on parameters notified through higher layer signaling (e.g., RRC) from the base station apparatus and a physical downlink control channel (for example, DCI) indicating a transmission timing of the SRS. The base station apparatus 10 uses the SRS to measure an uplink channel state (CSI Measurement). The base station apparatus 10 may perform timing alignment and closed loop transmission power control from measurement results obtained by receiving the SRS.

In FIG. 1, at least the following downlink physical channels are used in radio communication of the downlink r31. The downlink physical channels are used for transmitting information output from the higher layer.

-   -   Physical Broadcast Channel (PBCH)     -   Physical Downlink Control Channel (PDCCH)     -   Physical Downlink Shared Channel (PDSCH)

The PBCH is used for broadcasting a Master Information Block (MIB, a Broadcast Channel (BCH)) that is used commonly by the terminal apparatuses. The MIB is one of pieces of system information. For example, the MIB includes a downlink transmission bandwidth configuration and a System Frame number (SFN). The MIB may include information indicating at least some of numbers of a slot, a subframe, and a radio frame in which a PBCH is transmitted.

The PDCCH is used to transmit Downlink Control Information (DCI). For the downlink control information, multiple formats based on applications (also referred to as DCI formats) are defined. The DCI format may be defined based on the type and the number of bits of the DCI constituting a single DCI format. The downlink control information includes control information for downlink data transmission and control information for uplink data transmission. The DCI format for downlink data transmission is also referred to as downlink assignment (or downlink grant, DL Grant). The DCI format for uplink data transmission is also referred to as uplink grant (or uplink assignment, UL Grant).

The DCI format for downlink data transmission includes DCI format 1_0, DCI format 1_1, and the like. DCI format 1_0 is for fallback downlink data transmission, and includes bits the number of which is fewer than DCI format 1_1 supporting MIMO and the like. On the other hand, DCI format 1_1 is capable of notifying MIMO or multiple codewords transmission, ZP CSI-RS trigger, CBG transmission information, and the like, and a presence or absence, or the number of bits of some fields thereof are added in accordance with the configuration by the higher layer (e.g., RRC signaling, MAC CE). A single downlink assignment is used for scheduling a single PDSCH in a single serving cell. The downlink grant may be used for at least scheduling a PDSCH within the same slot/subframe as the slot/subframe in which the downlink grant has been transmitted. The downlink assignment in DCI format 1_0 includes the following fields. For example, the relevant fields include a DCI format identifier, a frequency domain resource assignment (resource block allocation for the PDSCH, resource allocation), a time domain resource assignment, VRB to PRB mapping, a Modulation and Coding Scheme (MCS) for the PDSCH (information indicating a modulation order and a coding rate), a NEW Data Indicator (NDI) indicating an initial transmission or retransmission, information for indicating the HARQ process number in the downlink, a Redundancy version (RV) indicating information on redundant bits added to the codeword during error correction coding, Downlink Assignment Index (DAI), a Transmission Power Control (TPC) command for the PUCCH, a resource indicator for the PUCCH, an indicator for HARQ feedback timing from the PDSCH, and the like. Note that the DCI format for each downlink data transmission includes information (fields) required for the application among the above-described information. Either or both of DCI format 1_0 and DCI format 1_1 may be used for activation and deactivation of the downlink SPS.

The DCI format for uplink data transmission includes DCI format 0_0, DCI format 0_1, and the like. DCI format 0_0 is for fallback uplink data transmission, and includes bits the number of which is fewer than DCI format 0_1 supporting MIMO and the like. On the other hand, DCI format 0_1 is capable of notifying MIMO or multiple codewords transmission, a SRS resource indicator, precoding information, antenna port information, SRS request information, CSI request information, CBG transmission information, uplink PTRS association, DMRS sequence initialization, and the like, and a presence or absence, or the number of bits of some fields thereof are added in accordance with the configuration by the higher layer (e.g., RRC signaling). A single uplink grant is used for notifying the terminal apparatus of scheduling of a single PUSCH in a single serving cell. The uplink grant in DCI format 0_0 includes the following fields. For example, the relevant fields include a DCI format identifier, a frequency domain resource assignment (information on resource block allocation for transmitting the PUSCH and a time domain resource assignment, a frequency hopping flag, information on the MCS for the PUSCH, RV, NDI, information indicating the HARQ process number in the uplink, a TPC command for the PUSCH, a Supplemental UL (UL/SUL) indicator, and the like. Either or both of DCI format 0_0 and DCI format 0_1 may be used for activation and deactivation of the uplink SPS.

For the MCS for the PDSCH/PUSCH, an index (MCS index) indicating a modulation order and target coding rate for the PDSCH/the PUSCH can be used. The modulation order is associated with a modulation scheme. The modulation orders “2”, “4”, and “6” indicate “QPSK,” “16QAM,” and “64QAM,” respectively. Furthermore, in a case that 256QAM and 1024QAM are configured by the higher layer (e.g., RRC signaling), the modulation orders “8” and “10” can be notified, and indicate “256QAM” and “1024QAM”, respectively. The target coding rate is used to determine a transport block size (TBS) that is the number of bits to be transmitted, depending on the number of resource elements (the number of resource blocks) of the PDSCH/PUSCH scheduled in the PDCCH. A communication system 1 (the base station apparatus 10 and the terminal apparatus 20) shares a method of calculating the transport block size by the MCS, the target coding rate, and the number of resource elements (the number of resource blocks) allocated for the PDSCH/PUSCH transmission.

The PDCCH is generated by adding a Cyclic Redundancy Check (CRC) to the downlink control information. In the PDCCH, CRC parity bits are scrambled with a prescribed identifier (also referred to as an exclusive OR operation, mask). The parity bits are scrambled with a Cell-Radio Network Temporary Identifier (C-RNTI), a Configured Scheduling (CS)-RNTI, a Temporary C (TC)-RNTI, a Paging (P)-RNTI, a System Information (SI)-RNTI, a Random Access (RA)-RNTI, or with an INT-RNTI, a Slot Format Indicator (SFI)-RNTI, a TPC-PUSCH-RNTI, a TPC-PUCCH-RNTI, or a TPC-SRS-RNTI. The C-RNTI and the CS-RNTI are identifiers for identifying the terminal apparatus in a cell by the dynamic scheduling and the SPS/grant free access, respectively. The Temporary C-RNTI is an identifier for identifying the terminal apparatus that has transmitted a random access preamble in a contention based random access procedure. The C-RNTI and the Temporary C-RNTI are used to control PDSCH transmission or PUSCH transmission in a single subframe. The CS-RNTI is used to periodically allocate a resource for the PDSCH or the PUSCH. The P-RNTI is used to transmit a paging message (Paging Channel (PCH)). The SI-RNTI is used to transmit the SIB, and the RA-RNTI is used to transmit a random access response (message 2 in a random access procedure). The SFI-RNTI is used to notify a slot format. The INT-RNTI is used to notify a Pre-emption. The TPC-PUSCH-RNTI and the TPC-PUCCH-RNTI, and the TPC-SRS-RNTI are used to notify transmission power control values of the PUSCH and the PUCCH, and the SRS, respectively. Note that the identifier may include a CS-RNTI for each configuration in order to configure multiple grant free accesses/SPSs. The DCI to which the CRC scrambled with the CS-RNTI is added can be used for activation, deactivation, parameter change, or retransmission control (ACK/NACK transmission) of the grant free access, and the parameter may include a resource configuration (a configuration parameter for a DMRS, a resource in a frequency domain and a time domain of the grant free access, an MCS used for the grant free access, the number of repetitions, with or without applying a frequency hopping, and the like).

The PDSCH is used to transmit the downlink data (the downlink transport block, DL-SCH). The PDSCH is used to transmit a system information message (also referred to as a System Information Block (SIB)). Some or all of the SIBs can be included in the RRC message.

The PDSCH is used to transmit the RRC signaling. The RRC signaling transmitted from the base station apparatus may be common to the multiple terminal apparatuses in the cell (unique to the cell). That is, the information common to the user equipments in the cell is transmitted using RRC signaling unique to the cell. The RRC signaling transmitted from the base station apparatus may be a message dedicated to a certain terminal apparatus (also referred to as dedicated signaling). In other words, user equipment-specific (UE-Specific) information may be transmitted using a message dedicated to the certain terminal apparatus.

The PDSCH is used to transmit the MAC CE. The RRC signaling and/or the MAC CE is also referred to as a higher layer signal (higher layer signaling). The PMCH is used to transmit multicast data (Multicast Channel (MCH)).

In the downlink radio communication in FIG. 1, a Synchronization signal (SS) and a Downlink Reference Signal (DL RS) are used as downlink physical signals.

The synchronization signal is used for the terminal apparatus to take synchronization in the frequency domain and the time domain in the downlink. The downlink reference signal is used for the terminal apparatus to perform the channel estimation/channel compensation on the downlink physical channel. For example, the downlink reference signal is used to demodulate the PBCH, the PDSCH, and the PDCCH. The downlink reference signal can be used for the terminal apparatus to measure the downlink channel state (CSI measurement). The downlink reference signal may include a Cell-specific Reference Signal (CRS), a Channel state information Reference Signal (CSI-RS), a Discovery Reference Signal (DRS), and a Demodulation Reference Signal (DMRS).

The downlink physical channel and the downlink physical signal are also collectively referred to as a downlink signal. The uplink physical channel and the uplink physical signal are also collectively referred to as an uplink signal. The downlink physical channel and the uplink physical channel are also collectively referred to as a physical channel. The downlink physical signal and the uplink physical signal are also collectively referred to as a physical signal.

The BCH, the UL-SCH, and the DL-SCH are transport channels. Channels used in the Medium Access Control (MAC) layer are referred to as transport channels. A unit of the transport channel used in the MAC layer is also referred to as a Transport Block (TB) or a MAC Protocol Data Unit (PDU). The transport block is a unit of data that the MAC layer delivers to the physical layer. In the physical layer, the transport block is mapped to a codeword, and coding processing and the like are performed for each codeword.

In higher layer processing, processing is performed on a layer higher than the physical layer, such as a Medium Access Control (MAC) layer, a Packet Data Convergence Protocol (PDCP) layer, a Radio Link Control (RLC) layer, and a Radio Resource Control (RRC) layer.

Processing is performed on a layer higher than the physical layer, such as a Medium Access Control (MAC) layer, a Packet Data Convergence Protocol (PDCP) layer, a Radio Link Control (RLC) layer, and a Radio Resource Control (RRC) layer.

A higher layer processing unit configures various RNTIs for each terminal apparatus. The RNTI is used for encryption (scrambling) of the PDCCH, the PDSCH, and the like. In the higher layer processing, the downlink data (transport block, DL-SCH) allocated to the PDSCH, the system information specific to the terminal apparatus (System Information Block: SIB), the RRC message, the MAC CE, and the like are generated or acquired from the higher node and output. In the higher layer processing, various kinds of configuration information of the terminal apparatus 20 are managed. Note that a part of the function of the radio resource control may be performed in the MAC layer or the physical layer.

In the higher layer processing, information on the terminal apparatus, such as the function supported by the terminal apparatus (UE capability), is received from the terminal apparatus 20. The terminal apparatus 20 transmits its own function to the base station apparatus 10 by a higher layer signaling (RRC signaling). The information on the terminal apparatus includes information for indicating whether the terminal apparatus supports a prescribed function or information for indicating that the terminal apparatus has completed introduction and testing of the prescribed function. The information for indicating whether the prescribed function is supported includes information for indicating whether the introduction and testing of the prescribed function have been completed.

In a case that the terminal apparatus supports the prescribed function, the terminal apparatus transmits information (parameters) for indicating whether the prescribed function is supported. In a case that the terminal apparatus does not support a prescribed function, the terminal apparatus may not transmit information (parameters) for indicating whether the prescribed function is supported. In other words, whether the prescribed function is supported is notified by whether information (parameters) for indicating whether the prescribed function is supported is transmitted. The information (parameters) for indicating whether the prescribed function is supported may be notified by using one bit of 1 or 0.

In FIG. 1, the base station apparatus 10 and the terminal apparatuses 20 support, in the uplink, Multiple Access (MA) using the grant free access (also referred to grant free access, grant less access, Contention-based access, Autonomous access, Resource allocation for uplink transmission without grant, type1 configured grant transmission, or the like, and hereinafter referred to as grant free access). The grant free access is a scheme in which the terminal apparatus transmits uplink data (such as a physical uplink channel) without performing a procedure to transmit a SR by the terminal apparatus and specifies a physical resource and transmission timing of data transmission by way of a UL Grant using the DCI by the base station apparatus (also referred to as UL Grant through L1 signaling). Thus, in addition to an allocation periodicity for available resources, a target received power, a value (α) of fractional TPC, the number of HARQ processes, and a RV pattern during repetitive transmission of the same transport, the terminal apparatus can receive, in advance through RRC signaling (SPS-config), a physical resource (resource assignment in the frequency domain, resource assignment in the time domain) that can be used for grant free access and a transmission parameter (that may include a cyclic shift or OCC of DMRS, an antenna port number, a position or the number of OFDM symbols in which DMRS is allocated, the number of repetitive transmissions of the same transport, and the like), as Configured Uplink Grant (rrcConfiguredUplinkGrant, configured uplink grant) in RRC signaling, and perform data transmission using the configured physical resource only in a case that the transmission data is in the buffer. In other words, in a case that the higher layer does not deliver transport blocks to transmit in the grant free access, data transmission in the grant free access is not performed. In a case that the terminal apparatus receives SPS-config, but does not receive Configured Uplink Grant through RRC signaling, the terminal apparatus can also perform similar data transmission in the SPS (type2 configured grant transmission) by SPS activation via the UL Grant.

There are following two types of grant free access. A first type is type 1 configured grant transmission (UL-TWG-type 1), that is a scheme in which the base station apparatus transmits transmission parameters for the grant free access to the terminal apparatus through higher layer signaling (e.g., RRC), and transmits start of grant (activation, RRC setup) and end of grant (deactivation, RRC release) of the data transmission in the grant free access, and change of the transmission parameters also through higher layer signaling. Here, the transmission parameters for the grant free access may include a physical resource (time domain and frequency domain resource assignment) that can be used for data transmission in the grant free access, a periodicity of the physical resource, an MCS, with or without applying repetitive transmission, the number of repetitions, an RV configuration for repetitive transmission, with or without applying a frequency hopping, a hopping pattern, a DMRS configuration (the number of OFDM symbols for front-loaded DMRS, configurations of cyclic shift and time spread, or the like), the number of HARQ processes, information on transform precoder, and information on a configuration for TPC. The transmission parameters and the start of grant of the data transmission related to the grant free access may be simultaneously configured, or the start of grant of the data transmission in the grant free access may be configured at different timings (in a case of a SCell, SCell activation, and the like) after the transmission parameters for the grant free access are configured. A second type is type 2 configured grant transmission (UL-TWG-type2), in which the base station apparatus transmits transmission parameters for the grant free access to the terminal apparatus through higher layer signaling (e.g., RRC), and transmits start of grant (activation) and end of grant (deactivation) of the data transmission in the grant free access, and change of the transmission parameters through DCI (L1 signaling). Here, a periodicity of the physical resource in RRC, the number of repetitions, an RV configuration for repetitive transmission, the number of HARQ processes, information on transform precoder, and information on a configuration for TPC may be included, and the start of grant (activation) based on the DCI may include a physical resource (resource block allocation) that can be used for the grant free access. The transmission parameters and the start of grant of the data transmission related to the grant free access may be simultaneously configured, or the start of grant of the data transmission in the grant free access may be configured at different timings after the transmission parameters for the grant free access are configured. The present invention may be applied to any grant free access described above.

On the other hand, Semi-Persistent Scheduling (SPS) technology is introduced in LTE, and periodic resource allocation is possible mainly in Voice over Internet Protocol (VoIP) applications. In the SPS, the DCI is used to perform start of grant (activation) by way of an UL Grant including the transmission parameters such as a physical resource designation (resource blocks allocation) and an MCS. Thus, two types (UL-TWG-type 1) performing the start of grant (activation) in the grant free access through higher layer signaling (e.g., RRC) differ from the SPS in the starting procedure. The UL-TWG-type 2 is the same in the point of performing the start of grant (activation) by way of the DCI (L1 signaling), but may be different in the point of being capable of being used in the SCell, the BWP, and the SUL, or of notifying the number of repetitions, and an RV configuration for repetitive transmission through RRC signaling. The base station apparatus may perform scrambling with different types of RNTI for the DCI (L1 signaling) used for the grant free access (UL-TWG-type 1 and UL-TWG-type 2) and the DCI used for the dynamic scheduling, or may perform scrambling with the same RNTI between the DCI used for the re-transmission control of the UL-TWG-type 1 and the DCI used for the activation and deactivation and the re-transmission control of the UL-TWG-type 2.

The base station apparatus 10 and the terminal apparatuses 20 may support non-orthogonal multiple access in addition to orthogonal multiple access. Note that the base station apparatus 10 and the terminal apparatuses 20 can support both the grant free access and the scheduled access (dynamic scheduling). Here, an “uplink scheduled access” refers to data transmission by the terminal apparatus 20 according to the following procedure. The terminal apparatus 20 requests a radio resource for transmitting uplink data to the base station apparatus 10 using the random access procedure (Random Access Procedure) or the SR. The base station apparatus provides an UL Grant to each terminal apparatus based on the RACH or the SR by way of the DCI. In a case that the terminal apparatus receives an UL Grant as the control information from the base station apparatus, the terminal apparatus transmits uplink data using a prescribed radio resource, based on an uplink transmission parameter included in the UL Grant.

The downlink control information for physical channel transmission in the uplink may include a shared field shared between the scheduled access and the grant free access. In this case, in a case that the base station apparatus 10 indicates transmission of the uplink physical channel using the grant free access, the base station apparatus 10 and the terminal apparatus 20 interpret a bit sequence stored in the shared field in accordance with a configuration for the grant free access (e.g., a look-up table defined for the grant free access). Similarly, in a case that the base station apparatus 10 indicates transmission of the uplink physical channel using the scheduled access, the base station apparatus 10 and the terminal apparatus 20 interpret the shared field in accordance with a configuration for the scheduled access. Transmission of the uplink physical channel in the grant free access is referred to as Asynchronous data transmission. Note that the transmission of the uplink physical channel in the scheduled is referred to as Synchronous data transmission.

In the grant free access, the terminal apparatus 20 may randomly select a radio resource for transmission of uplink data. For example, the terminal apparatus 20 has been notified, by the base station apparatus 10, of multiple candidates for available radio resources as a resource pool, and randomly selects a radio resource from the resource pool. In the grant free access, the radio resource in which the terminal apparatus 20 transmits the uplink data may be configured in advance by the base station apparatus 10. In this case, the terminal apparatus 20 transmits the uplink data using the radio resource configured in advance without receiving the UL Grant (including a physical resource designation) in the DCI. The radio resource includes multiple uplink multiple access resources (resources to which the uplink data can be mapped). The terminal apparatus 20 transmits the uplink data by using one or more uplink multiple access resources selected from the multiple uplink multiple access resources. Note that the radio resource in which the terminal apparatus 20 transmits the uplink data may be predetermined in the communication system including the base station apparatus 10 and the terminal apparatus 20. The radio resource for transmission of the uplink data may be notified to the terminal apparatus 20 by the base station apparatus 10 using a physical broadcast channel (e.g., Physical Broadcast Channel (PBCH)/Radio Resource Control (RRC)/system information (e.g. System Information Block (SIB)/physical downlink control channel (downlink control information, e.g., Physical Downlink Control Channel (PDCCH), Enhanced PDCCH (EPDCCH), MTC PDCCH (MPDCCH), and Narrowband PDCCH (NPDCCH)).

In the grant free access, the uplink multiple access resource includes a multiple access physical resource and a Multi-Access Signature Resource. The multiple access physical resource is a resource including time and frequency. The multiple access physical resource and the multi-access signature resource may be used to identify the uplink physical channel transmitted by each terminal apparatus. The resource blocks are units to which the base station apparatus 10 and the terminal apparatus 20 are capable of mapping the physical channel (e.g., the physical data shared channel or the physical control channel). Each of the resource blocks includes one or more subcarriers (e.g., 12 subcarriers or 16 subcarriers) in a frequency domain.

The multi-access signature resource includes at least one multi-access signature of multiple multi-access signature groups (also referred to as multi-access signature pools). The multi-access signature is information indicating a characteristic (mark or indicator) that distinguishes (identifies) the uplink physical channel transmitted by each terminal apparatus. Examples of the multi-access signature include a spatial multiplexing pattern, a spreading code pattern (a Walsh code, an Orthogonal Cover Code (OCC), a cyclic shift for data spreading, the sparse code, or the like), an interleaved pattern, a demodulation reference signal pattern (a reference signal sequence, the cyclic shift, the OCC, or IFDM)/an identification signal pattern, and transmit power, at least one of which is included in the multi-access signature. In the grant free access, the terminal apparatus 20 transmits the uplink data by using one or more multi-access signatures selected from the multi-access signature pool. The terminal apparatus 20 can notify the base station apparatus 10 of available multi-access signatures. The base station apparatus 10 can notify the terminal apparatus of a multi-access signature used by the terminal apparatus 20 to transmit the uplink data. The base station apparatus 10 can notify the terminal apparatus 20 of an available multi-access signature group by the terminal apparatus 20 to transmit the uplink data. The available multi-access signature group may be notified by using the broadcast channel/RRC/system information/downlink control channel. In this case, the terminal apparatus 20 can transmit the uplink data by using a multi-access signature selected from the notified multi-access signature group.

The terminal apparatus 20 transmits the uplink data by using a multiple access resource. For example, the terminal apparatus 20 can map the uplink data to a multiple access resource including a multi-carrier signature resource including one multiple access physical resource, a spreading code pattern, and the like. The terminal apparatus 20 can allocate the uplink data to a multiple access resource including a multi-carrier signature resource including one multiple access physical resource and an interleaved pattern. The terminal apparatus 20 can also map the uplink data to a multiple access resource including one multiple access physical resource and a multi-access signature resource including a demodulation reference signal pattern/identification signal pattern. The terminal apparatus 20 can also map the uplink data to a multiple access resource including one multiple access physical resource and a multi-access signature resource including a transmit power pattern (e.g., the transmit power for each of the uplink data may be configured to cause a difference in a received power at the base station apparatus 10). In such grant free access, the communication system of the present embodiment may allow the uplink data transmitted by the multiple terminal apparatuses 20 to overlap (be superimposed, spatially multiplexed, non-orthogonally multiplexed, collide) with one another and be transmitted in the uplink multiple access physical resource.

The base station apparatus 10 detects, in the grant free access, a signal of the uplink data transmitted by each terminal apparatus. To detect the uplink data signal, the base station apparatus 10 may include Symbol Level Interference Cancellation (SLIC) in which interference is canceled based on a demodulation result for an interference signal, Codeword Level Interference Cancellation (CWIC, also referred to as Sequential Interference Canceler (SIC) or Parallel Interference Canceler (PIC)) in which interference is canceled based on the decoding result for the interference signal, turbo equalization, maximum likelihood detection (MLD, Reduced complexity maximum likelihood detection (R-MLD)) in which transmit signal candidates are searched for the most probable signal, Enhanced Minimum Mean Square Error-Interference Rejection Combining (EMMSE-IRC) in which interference signals are suppressed by linear computation, signal detection based on message passing (Belief propagation (BP), Matched Filter (MF)-BP in which a matched filter is combined with BP, or the like.

FIG. 2 is a diagram illustrating an example of a radio frame structure for a communication system according to the present embodiment. The radio frame structure indicates a configuration of multiple access physical resources in a time domain. One radio frame includes multiple slots (or may include subframes). FIG. 2 is an example in which one radio frame includes 10 slots. The terminal apparatus 20 has a subcarrier spacing used as a reference (reference numerology). The subframe includes multiple OFDM symbols generated at the subcarrier spacings used as the reference. FIG. 2 is an example in which a subcarrier spacing is 15 kHz, one frame includes 10 slots, one subframe includes one slot, and one slot includes 14 OFDM symbols. In a case that the subcarrier spacing is 15 kHz×2μ (μ is an integer of 0 or more), one frame includes 2μ10 slots and one subframe includes 2μ slots.

FIG. 2 illustrates a case where the subcarrier spacing used as the reference is the same as a subcarrier spacing used for the uplink data transmission. The communication system according to the present embodiment may use slots as minimum units to which the terminal apparatus 20 maps the physical channel (e.g., the physical data shared channel or the physical control channel). In this case, in the multiple access physical resource, one slot is defined as a resource block unit in the time domain. Furthermore, in the communication system according to the present embodiment, a minimum unit for mapping the physical channel by the terminal apparatus 20 may be one or multiple OFDM symbols (e.g., 2 to 13 OFDM symbols). The base station apparatus 10 has one or multiple OFDM symbols serving as a resource block unit in the time domain. The base station apparatus 10 may signal a minimum unit for mapping a physical channel to the terminal apparatus 20.

FIG. 3 is a schematic block diagram illustrating a configuration of the base station apparatus 10 according to the present embodiment. The base station apparatus 10 includes a receive antenna 202, a receiver (receiving step) 204, a higher layer processing unit (higher layer processing step) 206, a controller (control step) 208, a transmitter (transmitting step) 210, and a transmit antenna 212. The receiver 204 includes a radio receiving unit (radio receiving step) 2040, a Fast Fourier Transform (FFT) unit 2041 (FFT step), a demultiplexing unit (demultiplexing step) 2042, a channel estimation unit (channel estimating step) 2043, and a signal detection unit (signal detecting step) 2044. The transmitter 210 includes a coding unit (coding step) 2100, a modulation unit (modulation step) 2102, a multiple access processing unit (multiple access processing step) 2106, a multiplexing unit (multiplexing step) 2108, a radio transmitting unit (radio transmitting step) 2110, an Inverse Fast Fourier Transform (IFFT) unit (IFFT step) 2109, a downlink reference signal generation unit (downlink reference signal generation step) 2112, and a downlink control signal generation unit (downlink control signal generation step) 2113.

The receiver 204 demultiplexes, demodulates, and decodes an uplink signal (uplink physical channel, uplink physical signal) received from the terminal apparatus 10 via the receive antenna 202. The receiver 204 outputs a control channel (control information) separated from the received signal to the controller 208. The receiver 204 outputs a decoding result to the higher layer processing unit 206. The receiver 204 acquires the SR and the ACK/NACK and CSI for the downlink data transmission included in the received signal.

The radio receiving unit 2040 converts, by down-conversion, an uplink signal received through the receive antenna 202 into a baseband signal, removes unnecessary frequency components from the baseband signal, controls an amplification level in such a manner as to suitably maintain a signal level, orthogonally demodulates the signal based on an in-phase component and an orthogonal component of the received signal, and converts the resulting orthogonally-demodulated analog signal into a digital signal. The radio receiving unit 2040 removes a portion of the digital signal resulting from the conversion, the portion corresponding to a Cyclic Prefix (CP). The FFT unit 2041 performs a fast Fourier transform on the downlink signal from which CP has been removed (demodulation processing for OFDM modulation), and extracts the signal in the frequency domain.

The channel estimation unit 2043 uses the demodulation reference signal to perform channel estimation for signal detection for the uplink physical channel. The channel estimation unit 2043 receives as inputs, from the controller 208, the resources to which the demodulation reference signal is mapped and the demodulation reference signal sequence allocated to each terminal apparatus. The channel estimation unit 2043 uses the demodulation reference signal sequence to measure the channel state between the base station apparatus 10 and the terminal apparatus 20. The channel estimation unit 2043, in a case of the grant free access, can identify the terminal apparatus by using the result of channel estimation (impulse response and frequency response with the channel state) (the channel estimation unit 2043 is thus also referred to as an identification unit). The channel estimation unit 2043 determines that an uplink physical channel has been transmitted by the terminal apparatus 20 associated with the demodulation reference signal from which the channel state has been successfully extracted. In the resource on which the uplink physical channel is determined by the channel estimation unit 2043 to have been transmitted, the demultiplexing unit 2042 extracts the signal in the frequency domain input from the FFT unit 2041 (the signal includes signals from multiple terminal apparatuses 20).

The demultiplexing unit 2042 separates and extracts the uplink physical channel (physical uplink control channel, physical uplink shared channel) and the like included in the extracted uplink signal in the frequency domain. The demultiplexing unit outputs the physical uplink channel to the signal detection unit 2044/controller 208.

The signal detection unit 2044 uses the channel estimation result estimated by the channel estimation unit 2043 and the signal in the frequency domain input from the demultiplexing unit 2042 to detect a signal of uplink data (uplink physical channel) from each terminal apparatus. The signal detection unit 2044 performs detection processing for a signal from the terminal apparatus 20 associated with the demodulation reference signal (demodulation reference signal from which the channel state has been successfully extracted) allocated to the terminal apparatus 20 determined to have transmitted the uplink data.

FIG. 4 is a diagram illustrating an example of the signal detection unit according to the present embodiment. The signal detection unit 2044 includes an equalization unit 2504, multiple access signal separation units 2506-1 to 2506-u, Inverse Discrete Fourier Transform (IDFT) units 2508-1 to 2508-u, demodulation units 2510-1 to 2510-u, and decoding units 2512-1 to 2512-u. u, in the case of the grant free access, represents the number of terminal apparatuses determined by the channel estimation unit 2043 to have transmitted uplink data (for which the channel state has been successfully extracted) on the same multiple access physical resource or overlapping multiple access physical resources (at the same time and at the same frequency). u, in the case of the scheduled access, represents the number of terminal apparatuses allowed to transmit uplink data on the same multiple access physical resource or overlapping multiple access physical resources in the DCI (at the same time, for example, OFDM symbols, slots). Each of the portions constituting the signal detection unit 2044 is controlled using the configuration related to the grant free access for each terminal apparatus and input from the controller 208.

The equalization unit 2504 generates an equalization weight based on the MMSE standard, from the frequency response input from the channel estimation unit 2043. Here, MRC and ZF may be used for the equalization processing. The equalization unit 2504 multiplies the equalization weight by the signal (including a signal of each terminal apparatus) in the frequency domain input from the demultiplexing unit 2042, and extracts the signal in the frequency domain for the terminal apparatus. The equalization unit 2504 outputs the equalized signal in the frequency domain from each terminal apparatus to the IDFT units 2508-1 to 2508-u. Here, in a case that data is to be detected that is transmitted by the terminal apparatus 20 and that uses the DFTS-OFDM signal waveform, the signal in the frequency domain is output to the IDFT units 2508-1 to 2508-u. In a case that data is to be received that is transmitted by the terminal apparatus 20 and that uses the OFDM signal waveform, the signal in the frequency domain is output to the multiple access signal separation units 2506-1 to 2506-u.

Each of the IDFT units 2508-1 to 2508-u converts the equalized signal in the frequency domain from each terminal apparatus into a signal in the time domain. Note that the IDFT units 2508-1 to 2508-u correspond to processing performed by the DFT unit of the terminal apparatus 20. Each of the multiple access signal separation units 2506-1 to 2506-u separates the signal multiplexed by the multi-access signature resource from the signal in the time domain from each terminal apparatus after conversion with the IDFT (multiple access signal separation processing). For example, in a case that code spreading is used as a multi-access signature resource, each of the multiple access signal separation units 2506-1 to 2506-u performs inverse spreading processing using the spreading code sequence assigned to each terminal apparatus. Note that, in a case that interleaving is applied as a multi-access signature resource, deinterleave processing is performed on the signal in the time domain from each terminal apparatus after conversion with the IDFT (deinterleaving unit).

Each of the demodulation units 2510-1 to 2510-u receives as an input, from the controller 208, pre-notified or predetermined information about the modulation scheme (BPSK, QPSK, 16QAM, 64QAM, 256QAM, and the like) of each terminal apparatus. Based on the information about the modulation scheme, the demodulation units 2510-1 to 2510-u perform demodulation processing on the signal after the multiple access signal separation, and outputs a Log Likelihood Ratio (LLR) of the bit sequence.

The decoding units 2512-1 to 2512-u receive as an input, from the controller 208, pre-notified or predetermined information about the coding rate. The decoding units 2512-1 to 2512-u perform decoding processing on the LLR sequences output from the demodulation units 2510-1 to 2510-u, respectively, and output the decoded uplink data/uplink control information to the higher layer processing unit 206. In order to perform cancellation processing such as a Successive Interference Canceller (SIC) or turbo equalization, the decoding units 2512-1 to 2512-u may generate replicas from external LLRs or post LLRs output from the decoding units and perform the cancellation processing. A difference between the external LLR and the post LLR is whether to subtract, from the decoded LLR, the pre LLR input to each of the decoding units 2512-1 to 2512-u. In a case that the number of repetitions of SIC or turbo equalization is larger than or equal to a prescribed value, each of the decoding units 2512-1 to 2512-u may perform hard decision on the LLR resulting from the decoding processing, and may output the bit sequence of the uplink data for each terminal apparatus to the higher layer processing unit 206. Note that the signal detection is not limited to that using the turbo equalization processing, and can be replaced with signal detection based on replica generation and using no interference cancellation, maximum likelihood detection, EMMSE-IRC, or the like.

The controller 208 controls the receiver 204 and the transmitter 210 by using the configuration information related to the uplink reception/configuration information related to the downlink transmission included in the uplink physical channel (physical uplink control channel, physical uplink shared channel, or the like) (notified from the base station apparatus to the terminal apparatus by way of the DCI, RRC, SIB, and the like). The controller 208 acquires the configuration information related to the uplink reception/configuration information related to the downlink transmission from the higher layer processing unit 206. In a case that the transmitter 210 transmits the physical downlink control channel, the controller 208 generates Downlink Control information (DCI) and outputs the generated information to the transmitter 210. Note that some of the functions of the controller 108 can be included in the higher layer processing unit 102. Note that the controller 208 may control the transmitter 210 in accordance with the parameter of the CP length added to the data signal.

The higher layer processing unit 206 performs processing of layers higher than the physical layer, such as the Medium Access Control (MAC) layer, the Packet Data Convergence Protocol (PDCP) layer, the Radio Link Control (RLC) layer, and the Radio Resource Control (RRC) layer. The higher layer processing unit 206 generates information needed to control the transmitter 210 and the receiver 204, and outputs the resultant information to the controller 208. The higher layer processing unit 206 outputs downlink data (e.g., the DL-SCH), broadcast information (e.g., the BCH), a Hybrid Automatic Request indicator (HARQ indicator), and the like to the transmitter 210. The higher layer processing unit 206 receives information, as an input, from the receiver 204, related to a function of the terminal apparatus (UE capability) supported by the terminal apparatus. For example, the higher layer processing unit 206 receives, through signaling in the RRC layer, information related to the function of the terminal apparatus.

The information related to the function of the terminal apparatus includes information indicating whether the terminal apparatus supports a prescribed function, or information indicating that the terminal apparatus has completed introduction and testing of a prescribed function. The information for indicating whether the prescribed function is supported includes information for indicating whether the introduction and testing of the prescribed function have been completed. In a case that the terminal apparatus supports the prescribed function, the terminal apparatus transmits information (parameters) for indicating whether the prescribed function is supported. In a case that the terminal apparatus does not support the prescribed function, the terminal apparatus may be configured not to transmit information (parameters) for indicating whether the prescribed function is supported. In other words, whether the prescribed function is supported is notified by whether information (parameters) for indicating whether the prescribed function is supported is transmitted. The information (parameters) for indicating whether the prescribed function is supported may be notified by using one bit of 1 or 0.

The information related to the function of the terminal apparatus includes information indicating that the grant free access is supported (information on whether or not each of the UL-TWG-type 1 and the UL-TWG-type 2 is supported). In a case that multiple functions corresponding to the grant free access are provided, the higher layer processing unit 206 can receive information indicating whether the grant free access is supported on a function-by-function basis. The information indicating that the grant free access is supported includes information indicating the multiple access physical resource and multi-access signature resource supported by the terminal apparatus. The information indicating that the grant free access is supported may include a configuration of a lookup table for the configuration of the multiple access physical resource and the multi-access signature resource. The information indicating that the grant free access is supported may include some or all of an antenna port, a capability corresponding to multiple tables indicating a scrambling identity and the number of layers, a capability corresponding to a prescribed number of antenna ports, and a capability corresponding to a prescribed transmission mode. The transmission mode is determined by the number of antenna ports, transmission diversity, the number of layers, and whether support of the grant free access and the like are provided.

The information related to the function of the terminal apparatus includes information indicating that a function related to URLLC is supported. Examples of a DCI format for the uplink dynamic scheduling, the SPS/grant free access, the downlink dynamic scheduling, and the SPS includes a compact DCI format that has the smaller total number of bits of the fields in the DCI format, and the information related to the function of the terminal apparatus may include information indicating that a receiving process on the compact DCI format (blind decoding) is supported. The DCI format is allocated and transmitted in a PDCCH search space, and the number of resources that can be used is determined for each aggregation level. Therefore, as the total number of bits of the fields in the DCI format increases, the coding rate of transmission becomes higher, and as the total number of bits of the fields in the DCI format decreases, the coding rate of transmission becomes lower. Therefore, in a case that high reliability such as that of URLLC is required, it is preferable to use the compact DCI format. Note that in LTE or NR, the DCI format is allocated in a predetermined resource element (search space). Therefore, in a case that the number of resource elements (aggregation level) is constant, the DCI format with a larger payload size provides a higher coding rate transmission compared to a DCI format with a smaller payload size, which makes it difficult to satisfy the high reliability.

The higher layer processing unit 206 manages various types of configuration information about the terminal apparatus. Some of the various types of configuration information are input to the controller 208. The various types of configuration information are transmitted from the base station apparatus 10 via the transmitter 210 using the downlink physical channel. The various types of configuration information include configuration information related to the grant free access input from the transmitter 210. The configuration information related to the grant free access includes configuration information about the multiple access resources (multiple access physical resources and multi-access signature resources). For example, the configuration information related to the grant free access may include a configuration related to the multi-access signature resource (configuration related to processing performed based on a mark for identifying the uplink physical channel transmitted by the terminal apparatus 20), such as an uplink resource block configuration (a starting position of the OFDM symbol to be used, the number of OFDM symbols/the number of resource blocks), a configuration of the demodulation reference signal/identification signal (reference signal sequence, cyclic shift, OFDM symbols to be mapped, and the like), a spreading code configuration (Walsh code, Orthogonal Cover Code (OCC), sparse code, spreading rates of these spreading codes, and the like), an interleave configuration, a transmit power configuration, a transmit and/or receive antenna configuration, and a transmit and/or receive beamforming configuration. These multi-access signature resources may be directly or indirectly associated (linked) with one another. The association of the multi-access signature resources is indicated by a multi-access signature process index. The configuration information related to the grant free access may include the configuration of the look-up table for the configuration of the multiple access physical resource and multi-access signature resource. The configuration information related to the grant free access may include setup of the grant free access, information indicating release, ACK/NACK reception timing information for uplink data signals, retransmission timing information for uplink data signals, and the like.

Based on the configuration information related to the grant free access that is notified as the control information, the higher layer processing unit 206 manages multiple access resources (multiple access physical resources, multi-access signature resources) for the uplink data (transport blocks) by way of grant free. Based on the configuration information related to the grant free access, the higher layer processing unit 206 outputs, to the controller 208, information used to control the receiver 204.

The higher layer processing unit 206 outputs generated downlink data (e.g., DL-SCH) to the transmitter 210. The downlink data may include a field storing the UE ID (RNTI). The higher layer processing unit 206 adds the CRC to the downlink data. The CRC parity bits are generated using the downlink data. The CRC parity bits are scrambled with the UE ID (RNTI) allocated to the destination terminal apparatus (the scrambling is also referred to as an exclusive-OR operation, masking, or ciphering). However, as described above, the multiple types of RNTI are provided, which are different depending on the data to be transmitted, and the like.

The higher layer processing unit 206 generates or acquires from a higher node, system information (MIB, SIB) to be broadcasted. The higher layer processing unit 206 outputs, to the transmitter 210, the system information to be broadcasted. The system information to be broadcasted can include information indicating that the base station apparatus 10 supports the grant free access. The higher layer processing unit 206 can include, in the system information, a portion or all of the configuration information related to the grant free access (such as the configuration information related to the multiple access resources such as the multiple access physical resource, the multi-access signature resource). The uplink system control information is mapped to the physical broadcast channel/physical downlink shared channel in the transmitter 210.

The higher layer processing unit 206 generates or acquires from a higher node, and outputs to the transmitter 210, downlink data (transport blocks) to be mapped to the physical downlink shared channel, system information (SIB), an RRC message, a MAC CE, and the like. The higher layer processing unit 206 can include, in this higher layer signaling, some or all of the configuration information related to the grant free access and parameters indicating setup and/or release of the grant free access. The higher layer processing unit 206 may generate a dedicated SIB for notifying the configuration information related to the grant free access.

The higher layer processing unit 206 maps the multiple access resources to the terminal apparatuses 20 supporting the grant free access. The base station apparatus 10 may hold a lookup table of configuration parameters for the multi-access signature resource. The higher layer processing unit 206 allocates each configuration parameter to the terminal apparatuses 20. The higher layer processing unit 206 uses the multi-access signature resource to generate the configuration information related to the grant free access for each terminal apparatus. The higher layer processing unit 206 generates a downlink shared channel including a portion or all of the configuration information related to the grant free access for each terminal apparatus. The higher layer processing unit 206 outputs, to the controller 208/transmitter 210, the configuration information related to the grant free access.

The higher layer processing unit 206 configures a UE ID for each terminal apparatus and notifies the terminal apparatus of the UE ID. As the UE ID, a Cell Radio Network Temporary Identifier (RNTI) can be used. The UE ID is used for the scrambling of the CRC added to the downlink control channel and the downlink shared channel. The UE ID is used for scrambling of the CRC added to the uplink shared channel. The UE ID is used to generate an uplink reference signal sequence. The higher layer processing unit 206 may configure a SPS/ grant free access-specific UE ID. The higher layer processing unit 206 may configure the UE ID separately depending on whether or not the terminal apparatus supports the grant free access. For example, in a case that the downlink physical channel is transmitted in the scheduled access and the uplink physical channel is transmitted in the grant free access, the UE ID for the downlink physical channel may be configured separately from the UE ID for the downlink physical channel. The higher layer processing unit 206 outputs the configuration information related to the UE ID to the transmitter 210/controller 208/receiver 204.

The higher layer processing unit 206 determines the coding rate, the modulation scheme (or MCS), the transmit power, and the like for the physical channels (physical downlink shared channel, physical uplink shared channel, and the like). The higher layer processing unit 206 outputs the coding rate/modulation scheme/transmit power to the transmitter 210/controller 208/receiver 204. The higher layer processing unit 206 can include the coding rate/modulation scheme/transmit power in higher layer signaling.

In a case that the downlink data to be transmitted is generated, the transmitter 210 transmits the physical downlink shared channel. In a case that the transmitter 210 is transmitting a resource for data transmission by way of the DL Grant, the transmitter 210 may transmit the physical downlink shared channel using the scheduled access, and transmit the physical downlink shared channel using the SPS in a case that the SPS is activated. The transmitter 210 generates the physical downlink shared channel and the demodulation reference signal/control signal associated with the physical downlink shared channel in accordance with the configuration related to the scheduled access/SPS input from the controller 208.

The coding unit 2100 codes the downlink data input from the higher layer processing unit 206 by using the predetermined coding scheme/coding scheme configured by the controller 208 (the coding includes repetitions). The coding scheme may involve application of convolutional coding, turbo coding, Low Density Parity Check (LDPC) coding, Polar coding, and the like. The LDPC code may be used for data transmission, whereas the Polar code may be used for transmission of the control information. Different error correction coding may be used depending on the downlink channel to be used. Different error correction coding may be used depending on the size of the data or control information to be transmitted. For example, the convolution code may be used in a case that the data size is smaller than a prescribed value, and otherwise the correction coding described above may be used. For the coding described above, in addition to a coding rate of ⅓, a mother code such as a low coding rate of ⅙ or 1/12 may be used. In a case that a coding rate higher than the mother code is used, the coding rate used for data transmission may be achieved by rate matching (puncturing). The modulation unit 2102 modulates coded bits input from the coding unit 2100, in compliance with a modulation scheme notified by way of the downlink control information or a modulation scheme predetermined for each channel, such as BPSK, QPSK, 16QAM, 64QAM, or 256QAM (the modulation scheme may include π/2 shift BPSK or π/4 shift QPSK).

The multiple access processing unit 2106 performs signal conversion such that the base station apparatus 10 can achieve signal detection even in a case that multiple data are multiplexed on a sequence output from the modulation unit 2102 in accordance with multi-access signature resource input from the controller 208. In a case that the multi-access signature resource is configured as spreading, multiplication by the spreading code sequence is performed according to the configuration of the spreading code sequence. Note that, in a case that interleaving is configured as a multi-access signature resource in the multiple access processing unit 2106, the multiple access processing unit 2106 can be replaced with an interleave unit. The interleave unit performs interleave processing on the sequence output from the modulation unit 2102 in accordance with the configuration of the interleave pattern input from the controller 208. In a case that code spreading and interleaving are configured as a multi-access signature resource, the multiple access processing unit 2106 of the transmitter 210 performs spreading processing and interleaving. A similar operation is performed even in a case that any other multi-access signature resource is applied, and the sparse code or the like may be applied.

In a case that the OFDM signal waveform is used, the multiple access processing unit 2106 inputs the multiple-access-processed signal to the multiplexing unit 2108. The downlink reference signal generation unit 2112 generates a demodulation reference signal in accordance with the configuration information about the demodulation reference signal input from the controller 208. The configuration information about the demodulation reference signal/identification signal is used to generate a sequence acquired according to a rule determined in advance, based on information such as the number of OFDM symbols notified by the base station apparatus by way of the downlink control information, the OFDM symbol position in which the DMRS is allocated, the cyclic shift, and the time domain spreading.

The multiplexing unit 2108 multiplexes (maps, allocates) the downlink physical channel and the downlink reference signal to resource elements for each transmit antenna port. In a case that the SCMA is used, the multiplexing unit 2108 allocates the downlink physical channel to the resource elements in accordance with an SCMA resource pattern input from the controller 208.

The IFFT unit 2109 performs the Inverse Fast Fourier Transform (IFFT) on the multiplexed signal to perform OFDM modulation to generate OFDM symbols. The radio transmitting unit 2110 adds CPs to the OFDM-modulated symbols to generate a baseband digital signal. Furthermore, the radio transmitting unit 2110 converts the baseband digital signal into an analog signal, removes the excess frequency components from the analog signal, converts the signal into a carrier frequency by up-conversion, performs power amplification, and transmits the resultant signal to the terminal apparatus 20 via the transmit antenna 212. The radio transmitting unit 2110 includes a transmit power control function (transmit power controller). The transmit power control follows configuration information about the transmit power input from the controller 208. Note that, in a case that FBMC, UF-OFDM, or F-OFDM is applied, filtering is performed on the OFDM symbols in units of subcarriers or sub-bands.

FIG. 5 is a schematic block diagram illustrating a configuration of the terminal apparatus 20 according to the present embodiment. The base station apparatus 10 includes a higher layer processing unit (higher layer processing step) 102, a transmitter (transmitting step) 104, a transmit antenna 106, a controller (control step) 108, a receive antenna 110, and a receiver (receiving step) 112. The transmitter 104 includes a coding unit (coding step) 1040, a modulation unit (modulating step) 1042, a multiple access processing unit (multiple access processing step) 1043, a multiplexing unit (multiplexing step) 1044, a DFT unit (DFT step) 1045, an uplink control signal generation unit (uplink control signal generating step) 1046, an uplink reference signal generation unit (uplink reference signal generating step) 1048, an IFFT unit 1049 (IFFT step), and a radio transmitting unit (radio transmitting step) 1050. The receiver 112 includes a radio receiving unit (radio receiving step) 1120, an FFT unit (FFT step) 1121, a channel estimation unit (channel estimating step) 1122, a demultiplexing unit (demultiplexing step) 1124, and a signal detection unit (signal detecting step) 1126.

The higher layer processing unit 102 performs processing of layers higher than the physical layer, such as the Medium Access Control (MAC) layer, the Packet Data Convergence Protocol (PDCP) layer, the Radio Link Control (RLC) layer, and the Radio Resource Control (RRC) layer. The higher layer processing unit 102 generates information needed to control the transmitter 104 and the receiver 112, and outputs the resultant information to the controller 108. The higher layer processing unit 102 outputs, to the transmitter 104, uplink data (e.g., UL-SCH), uplink control information, and the like.

The higher layer processing unit 102 transmits information related to the terminal apparatus, such as the function of the terminal apparatus (UE capability), from the base station apparatus 10 (via the transmitter 104). The information of the terminal apparatus includes information indicating that the grant free access or reception/detection/blind decoding of the compact DCI is supported, and information indicating whether such functions are supported on a per function basis. The information indicating that the grant free access is supported and the information indicating whether the grant free access is supported on a per function basis may be identified depending on the transmission mode.

Based on the various types of configuration information input from the higher layer processing unit 102, the controller 108 controls the transmitter 104 and the receiver 112. The controller 108 generates the uplink control information (UCI), based on the configuration information related to the control information input from the higher layer processing unit 102, and outputs the generated information to the transmitter 104.

The transmitter 104 codes and modulates the uplink control information, the uplink shared channel, and the like input from the higher layer processing unit 102 for each terminal apparatus, to generate a physical uplink control channel and a physical uplink shared channel. The coding unit 1040 codes the uplink control information and the uplink shared channel by using the predetermined coding scheme/coding scheme notified by way of the control information (the coding includes repetitions). The coding scheme may involve application of convolutional coding, turbo coding, Low Density Parity Check (LDPC) coding, Polar coding, and the like. The modulation unit 1042 modulates the coded bits input from the coding unit 1040 by using a predetermined modulation scheme/a modulation scheme notified by way of the control information, such as the BPSK, QPSK, 16QAM, 64QAM, or 256QAM.

The multiple access processing unit 1043 performs signal conversion such that the base station apparatus 10 can achieve signal detection even in a case multiple pieces of data are multiplexed on a sequence output from the modulation unit 1042 in accordance with the multi-access signature resource input from the controller 108. In a case that the multi-access signature resource is configured as spreading, multiplication by the spreading code sequence is performed according to the configuration of the spreading code sequence. The configuration of the spreading code sequence may be associated with other configurations of the grant free access such as the demodulation reference signal/identification signal. Note that the multiple access processing may be performed on the sequence after the DFT processing. Note that, in a case that interleaving is configured as a multi-access signature resource in the multiple access processing unit 1043, the multiple access processing unit 1043 can be replaced with an interleave unit. The interleave unit performs interleave processing on the sequence output from the DFT unit in accordance with the configuration of the interleave pattern input from the controller 108. In a case that code spreading and interleaving are configured as a multi-access signature resource, the multiple access processing unit 1043 of the transmitter 104 performs spreading processing and interleaving. A similar operation is performed even in a case that any other multi-access signature resource is applied, and the sparse code or the like may be applied.

The multiple access processing unit 1043 inputs the multiple-access-processed signal to the DFT unit 1045 or the multiplexing unit 1044 depending on whether a DFTS-OFDM signal waveform or an OFDM signal waveform is used. In a case that the DFTS-OFDM signal waveform is used, the DFT unit 1045 rearranges multiple-access-processed modulation symbols output from the multiple access processing unit 1043 in parallel and then performs Discrete Fourier Transform (DFT) processing on the rearranged modulation symbols. Here, a zero symbol sequence may be added to the modulation symbols, and the DFT may then be performed to provide a signal waveform in which, instead of a CP, a zero interval is used for a time signal resulting from IFFT. A specific sequence such as Gold sequence or a Zadoff-Chu sequence may be added to the modulation symbols, and the DFT may then be performed to provide a signal waveform in which, instead of a CP, a specific pattern is used for the time signal resulting from the IFFT. In a case that the OFDM signal waveform is used, the DFT is not applied, and thus, the multiple-access-processed signal is input to the multiplexing unit 1044. The controller 108 performs control using a configuration of the zero symbol sequence (the number of bits in the symbol sequence and the like) and a configuration of the specific sequence (sequence seed, sequence length, and the like), the configurations being included in the configuration information related to the grant free access.

The uplink control signal generation unit 1046 adds the CRC to the uplink control information input from the controller 108, to generate a physical uplink control channel. The uplink reference signal generation unit 1048 generates an uplink reference signal.

The multiplexing unit 1044 maps each of the modulation symbols of the uplink physical channels modulated by the multiple access processing unit 1043 and the DFT unit 1045, the physical uplink control channel, and the uplink reference signal to the resource elements. The multiplexing unit 1044 maps the physical uplink shared channel and the physical uplink control channel to resources allocated to each terminal apparatus.

The IFFT unit 1049 performs Inverse Fast Fourier Transform (IFFT) on the modulation symbols of each multiplexed uplink physical channel to generate OFDM symbols. The radio transmitting unit 1050 adds cyclic prefixes (CPs) to the OFDM symbols to generate a baseband digital signal. Furthermore, the radio transmitting unit 1050 converts the digital signal into an analog signal, removes excess frequency components from the analog signal by filtering, performs up-conversion to the carrier frequency, performs power amplification, and outputs the resultant signal to the transmit antenna 106 for transmission.

The receiver 112 uses the demodulation reference signal to detect the downlink physical channel transmitted from the base station apparatus 10. The receiver 112 detects the downlink physical channel, based on the configuration information notified by the base station apparatus by way of the control information (such as DCI, RRC, SIB). Here, the receiver 112 performs blind decoding, for the search space included in the PDCCH, on a candidate that is predetermined or notified by way of higher layer control information (RRC signaling). The receiver 112 detects the DCI using the CRC scrambled with the C-RNTI, the CS-RNTI, and other RNTI, as a result of the blind decoding. The blind decoding may be performed by the signal detection unit 1126 in the receiver 112, or may be performed by a control signal detection unit (control information detection unit) which is not illustrated in the drawing, but may be provided additionally. In a case that the receiver 112 detects/receives the RRC, the signal detection unit 1126 in the receiver 112 may detect/receive the RRC.

The radio receiving unit 1120 converts, by down-conversion, an uplink signal received through the receive antenna 110 into a baseband signal, removes unnecessary frequency components from the baseband signal, controls the amplification level in such a manner as to suitably maintain a signal level, performs orthogonal demodulation based on an in-phase component and an orthogonal component of the received signal, and converts the resulting orthogonally-demodulated analog signal into a digital signal. The radio receiving unit 1120 removes a part corresponding to the CP from the converted digital signal. The FFT unit 1121 performs Fast Fourier Transform (FFT) on the signal from which the CPs have been removed, and extracts a signal in the frequency domain.

The channel estimation unit 1122 uses the demodulation reference signal to perform channel estimation for signal detection for the downlink physical channel. The channel estimation unit 1122 receives as inputs, from the controller 108, the resources to which the demodulation reference signal is mapped and the demodulation reference signal sequence allocated to each terminal apparatus. The channel estimation unit 1122 uses the demodulation reference signal sequence to measure the channel state between the base station apparatus 10 and the terminal apparatus 20. The demultiplexing unit 1124 extracts the signal in the frequency domain input from the radio receiving unit 1120 (the signal includes signals from multiple terminal apparatuses 20). The signal detection unit 1126 uses the channel estimation result and the signal in the frequency domain input from the demultiplexing unit 1124 to detect a signal of downlink data (uplink physical channel).

The higher layer processing unit 102 acquires the downlink data (bit sequence resulting from hard decision) from the signal detection unit 1126. The higher layer processing unit 102 performs descrambling (exclusive-OR operation) on the CRC included in the decoded downlink data for each terminal apparatus, by using the UE ID (RNTI) allocated to each terminal. In a case that no error is found in the downlink data as a result of the descrambling error detection, the higher layer processing unit 102 determines that the downlink data has been correctly received.

FIG. 6 is a diagram illustrating an example of the signal detection unit according to the present embodiment. The signal detection unit 1126 includes an equalization unit 1504, multiple access signal separation units 1506-1 to 1506-c, demodulation units 1510-1 to 1510-c, and decoding units 1512-1 to 1512-c.

The equalization unit 1504 generates equalization weights, based on the MMSE standard, from the frequency response input from the channel estimation unit 1122. Here, MRC and ZF may be used for the equalization processing. The equalization unit 1504 multiplies the equalization weights by the signal in the frequency domain input from the demultiplexing unit 1124, and extracts the signal in the frequency domain. The equalization unit 1504 outputs the equalized signal in the frequency domain to the multiple access signal separation units 1506-1 to 1506-c. c represents a numeral of 1 or greater, and represents the number of signals received in the same subframe, the same slot, or the same OFDM symbols, such as PUSCH and PUCCH. Reception of other downlink channels may be reception at the same timing.

Each of the multiple access signal separation units 1506-1 to 1506-c separates the signal multiplexed by the multi-access signature resource from the signal in the time domain (multiple access signal separation processing). For example, in a case that code spreading is used as a multi-access signature resource, each of the multiple access signal separation units 1506-1 to 1506-c performs inverse spreading processing using the used spreading code sequence. Note that, in a case that interleaving is applied as a multi-access signature resource, deinterleave processing is performed on the signal in the time domain (deinterleaving unit).

The demodulation units 1510-1 to 1510-c receive as an input, from the controller 108, pre-notified or predetermined information about the modulation scheme. Based on the information about the modulation scheme, the demodulation units 1510-1 to 1510-c perform demodulation processing on the signal after the multiple access signal, and outputs a Log Likelihood Ratio (LLR) of the bit sequence.

The decoding units 1512-1 to 1512-c receive as an input, from the controller 108, pre-notified or predetermined information about the coding rate. The decoding units 1512-1 to 1512-c perform decoding processing on the LLR sequences output from the demodulation units 1510-1 to 1510-c. In order to perform cancellation processing such as a Successive Interference Canceller (SIC) or turbo equalization, the decoding units 1512-1 to 1512-c may generate replicas from external LLRs or post LLRs output from the decoding units and perform the cancellation processing. A difference between the external LLR and the post LLR is whether to subtract, from the decoded LLR, the pre LLR input to each of the decoding units 1512-1 to 1512-c.

Uplink transmission power control is calculated by P_(PUSCH, f, c)(i, j, q_(d), l)=min{P_(CMAX, f, c)(i), P_(O_PUSCH, f, c)(j)+10 log₁₀(2^(μ)MPUSCH_(_RB, f, c)(i))+α_(f, c)(q_(d))+Δ_(TF, f, c)(i)+f_(f, c)(i, l)}. Here, min represents selection of a small value within { }. P_(CMAX, f, c)(i) is an allowable maximum transmit power of the terminal apparatus for carrier f of serving cell c in the i-th subframe, and P_(O_PUSCH, f, c)(j) is a nominal target received power configured through higher layer (RRC) for carrier f of serving cell c in scheduling j per RB, j is a value dependent on a type of scheduling or a transmission signal, where multiple values for j are configured through higher layer (RRC) such as j=0 for RACH, j=1 for a SPS/grant free access, and j=2 to j−1 for dynamic scheduling, and then, are designated in the DCI (e.g., the SRS Resource Indicator (SRI) field), α_(f, c)(j) is a parameter for the fractional transmission power control for carrier f of serving cell c, PL_(f, c)(q_(d)) is a path loss of serving cell c in resource q_(d) for a path loss measurement reference signal, Δ_(TF, f c)(i) is a parameter by a modulation order for carrier f of serving cell c in the i-th subframe, f_(f, c)(i, l) is a parameter notified from the base station apparatus to the terminal apparatus to perform closed loop control for carrier f of serving cell c, and l is a variable for enabling multiple closed loops control. For example, l=1 is usually given, and in a case that l={1, 2} is configured through higher layer (RRC), reflect on only one is possible by transmitting a TPC command of one of l=1 or l=2. l=1 and l=2 may be differently used by configuring the value of l used for the SPS/grant free access to use the other for dynamic scheduling. P_(O_PUSCH, f, c)(j) used to calculate the transmit power is determined by the sum of P_(O_NOMINAL_PUSCH, f, c)(j) and P_(O_UE_PUSCH, f, c)(j). A value of P_(O_NOMINAL_PUSCH, f, c)(j) is determined by the sum of the P_(O_PRE) notified through higher layer (RRC) and Δ_(PREAMBLE_Msg3) in a case of j=0, and configured through higher layer (RRC) in a case of j=1 or 2, where multiple values for SPS/grant free access and dynamic scheduling are configured for each case. A value of P_(O_UE_PUSCH, c)(j) is 0 in a case that j=0, and notified through higher layer (RRC) in a case of j=1 or 2, where multiple values for SPS/grant free access and dynamic scheduling are configured for each case.

A value of P_(CMAX, f, c)(i) is configured to be between P_(CMAX_L,c)(i) and P_(CMAX_H, c)(i) according to a capability of a Power Amplifier (Pa) of the terminal apparatus, P_(CMAX_L,c)(i) being determined from Maximum Power Reduction (MPR), Additional-MPR (A-MPR), and Power Management-MPR (P-MPR), P_(CMAX_H, c)(i) being determined from P_(EMAX, c) and P_(PowerClass).

Only the target received power P_(O_PUSCH, f, c)(j) and the parameter for the fractional transmission power control α_(f, c)(j) dependent on the type of scheduling can be designated in the DCI and dynamically changed. In a case that which of the multiple target received powers P_(O_PUSCH, f, c)(j) is used in the dynamic scheduling is designated by the SRI in the DCI, an SRI field in DCI format 0_1 supporting the multi-antenna transmission is used because fallback DCI format 0_0 includes no SRI field.

In the URLLC data transmission, not only the reliability of the PUSCH data transmission, but also the reliability of the DCI format transmitted on the PDCCH that allows data transmission is also important. Here, in a case that an error rate of the DCI format is P_(CONT) and an error rate of the data is P_(DATA), an error rate P_(Total) of the uplink including the DCI format detection rate is given as P_(Total)=1−(1−P_(CONT))(1−P_(DATA)). In other words, because P_(Total) needs to implement the required reliability (error rate), not only the reliability of the uplink data transmission (P_(DATA)) but also the reliability of the DCI format detection (P_(CONT)) are also important. Here, in LTE or NR, the DCI format is allocated in a predetermined resource element (search space). Therefore, in a case that the number of resource elements (aggregation level) is constant, the DCI format with a larger payload size provides a higher coding rate transmission compared to a DCI format with a smaller payload size, which makes it difficult to satisfy the high reliability.

Here, the compact DCI (Small Size DCI) in which the payload size of DCI format 0_0/0_1 for uplink data transmission is reduced is hereinafter referred to as a compact DCI for uplink data transmission and represented as DCI format 0_c. The compact DCI (Small Size DCI) in which the payload size of DCI format 1_0/1_1 for downlink data transmission is reduced is hereinafter referred to as a compact DCI for downlink data transmission and represented as DCI format 1_c. Examples of DCI format 0_c and DCI format 1_c may include those obtained by reducing the number of bits in each field of DCI format 0_0 and DCI format 1_0 or omitting some of the fields and being notified by way of higher layer control (RRC signaling), or those implemented as predetermined values. Specifically, in DCI format 0_c and DCI format 1_c, the number of bits may be reduced by limiting (reducing a specified value of) a starting position of the frequency-domain resource allocation or the number of RBs, or the number of bits may be reduced by limiting (reducing a specified value of) at least some of a position of the OFDM symbol where the time-domain resource allocation starts, the number of OFDM symbols used for data transmission, and the number of slots from the reception of the DCI format to the data transmission. In DCI format 0_c and DCI format 1_c, specified entries of the MCS may be reduced (e.g., the MCS having a higher modulation order and a higher coding rate cannot be specified, or the entry of an even number or an odd number cannot be specified). For example, DCI format 0_c and DCI format 1_c may have the MCS of 3 bits or 4 bits, and DCI format 0_0/0_1 and DCI format 1_0/1_1 may have the MCS of 5 bits. In DCI format 0_c and DCI format 1_c, the specified HARQ process number may be limited to reduce the number of bits.

Since the URLLC data transmission is a traffic in which not only high reliability but also low latency are required, it is preferable to be able to utilize the RACH or the SR that is a resource request before the data transmission, or the SPS/grant free access that does not require reception of the UL Grant in the DCI format. For this reason, the grant free access (Configured Uplink Grant) may be configured for the URLLC data transmission, and the dynamic scheduling (uplink grant addressed to the C-RNTI) may be configured for non-URLLC data transmission. However, in a case that the uplink grant addressed to the C-RNTI of the dynamic scheduling overlaps in the time domain with the Configured Uplink Grant of the SPS/grant free access, only the uplink grant addressed to the C-RNTI of the dynamic scheduling may be used regardless of the data requirement. (the uplink grant addressed to the C-RNTI of the dynamic scheduling override the Configured Uplink Grant.)

FIG. 7 is a diagram illustrating an example of a known notification of an uplink grant. In the figure, activation of the Configured Uplink Grant of the SPS/grant free access is notified in the DCI format on the PDCCH in a slot x, as described above, and the uplink grant addressed to the C-RNTI is notified in the DCI format on the PDCCH in a slot x+1. At this time, the uplink grants overlap (overlap in the time domain) in the uplink slots x+2 and x+3, so only the uplink grant addressed to the C-RNTI is used.

The present embodiment illustrates a method for switching the uplink grant to be used between the uplink grant addressed to the C-RNTI of the dynamic scheduling and the Configured Uplink Grant of the SPS/grant free access. In the present embodiment, the uplink grant to be used is switched depending on types of the DCI format notifying the uplink grant addressed to the C-RNTI (dynamic scheduling) and the DCI format notifying the Configured Uplink Grant. First, in the uplink grant addressed to the C-RNTI, the notification using DCI format 0_0/0_1 and DCI format 0_c that is the compact DCI is allowed, and DCI format 0_c is used for the data transmission in which high reliability is required. Next, in the SPS type 2 Configured Uplink Grant, DCI format 0_0/0_1 and DCI format 0_c that is the compact DCI can be used for the activation, and DCI format 0_c is used for the data transmission in which high reliability is required to perform the activation.

The terminal apparatus performs blind decoding of the predetermined search space in the PDCCH to detect the DCI format. In a case that the blind decoding is set up for one or both of DCI format 0_c that is the compact DCI and DCI format 1_c by way of higher layer control information (RRC signaling), the terminal apparatus performs the blind decoding of DCI format 0_0/0_1 and DCI format 0_c for uplink configuration, and the blind decoding of DCI format 1_0/1_1 and DCI format 1_c for downlink configuration.

FIG. 8 is a diagram illustrating an example of a notification of an uplink grant according to the first embodiment. The figure illustrates an example in which activation of the configured uplink grant (SPS/grant free access Type 2) is notified in the Compact DCI on the PDCCH in the slot x, and the configured uplink grant is present in each of the slot x+1 and subsequent slots (radio resource allocation of one slot periodicity). Next, the uplink grant addressed to the C-RNTI is notified in DCI format 0_0/0_1 in the slot x+1, and the uplink grant addressed to the C-RNTI is configured in the slot x+2 and the slot x+3. In this case, in the slot x+2 and the slot x+3, the uplink grant addressed to the C-RNTI overlaps in the time domain with the configured uplink grant in the Compact DCI (overlap in at least some of the OFDM symbols). In this case, the data transmission may be performed using only the configured uplink grant in the Compact DCI. This means that only the configured uplink grant using the Compact DCI is used, regardless of the type of scheduling such as dynamic scheduling and the SPS.

In a case that the uplink grant to be used is determined according to the DCI format, the traffic (buffer status) of the terminal apparatus may also be considered. This means that in the grant free access/SPS, the data transmission is performed according to the configured uplink grant only in a case that data to be transmitted is present, otherwise the data transmission is not performed according to the configured uplink grant. Here, the absence of data to be transmitted may mean that the transport block (TB) transmitted by the higher layer on the resource allocated for the grant free access/SPS (uplink transmission without grant) is not delivered.

As illustrated in FIG. 8, in a case that the uplink grant addressed to the C-RNTI overlaps in the time domain with the configured uplink grant in the Compact DCI, and that a traffic for the uplink grant addressed to the C-RNTI is present and no traffic for the configured uplink grant in the Compact DCI is present, the uplink grant addressed to the C-RNTI may be used. As illustrated in FIG. 8, in a case that the uplink grant addressed to the C-RNTI overlaps in the time domain with the configured uplink grant in the Compact DCI, and that a traffic for the configured uplink grant in the Compact DCI is present, the configured uplink grant in the Compact DCI may be used, regardless of whether a traffic for the uplink grant addressed to the C-RNTI is present or not.

On the other hand, FIG. 7 illustrates an example in which activation of the configured uplink grant (SPS/grant free access Type 2) is notified in DCI format 0_0/0_1 on the PDCCH in the slot x, and the configured uplink grant is present in each of the slot x+1 and subsequent slots (radio resource allocation of one slot periodicity). In this case, the uplink grant addressed to the C-RNTI is notified in DCI format 0_0/0_1 in the slot x+1, and the uplink grant addressed to the C-RNTI is configured in the slot x+2 and the slot x+3. As a result, in the slot x+2 and the slot x+3, the uplink grant addressed to the C-RNTI overlaps in the time domain with the configured uplink grant in DCI format 0_0/0_1 (overlap in at least a part of the OFDM symbols). Both the uplink grant addressed to the C-RNTI and the configured uplink grant are notified in DCI format 0_0/0_1, and thus, the same DCI format is used. In this case, the uplink grant to be used may be determined depending on the type of scheduling, and the uplink grant addressed to the C-RNTI may override the configured uplink grant.

As illustrated in FIG. 7, in the situation that the uplink grant addressed to the C-RNTI overlaps in the time domain with the configured uplink grant in DCI format 0_0/0_1 (overlap in at least a part of the OFDM symbols), in a case that a traffic for the configured uplink grant in DCI format 0_0/0_1 is present and no traffic for the uplink grant addressed to the C-RNTI is present, the configured uplink grant in DCI format 0_0/0_1 may be used.

Here, the uplink grant corresponding to the traffic may be determined depending on the Quality of Service (QoS), and may be determined depending on QoS Class Indicator (QCI) information, for example.

Note that in the present embodiment, the uplink grant to be used is determined depending on the DCI format, but the uplink grant to be used may be determined depending on the search space in which the DCI format has been detected, or the uplink grant to be used may be determined depending on both the DCI format and the search space. For example, only the uplink grant in the DCI format detected in the common search space may be used, and the uplink grant in the DCI format detected in the user-specific search space may not be used.

Note that in the present embodiment, the description is given assuming that the types of uplink grants in DCI format 0_0 and DCI format 0_1 are the same, but the types of uplink grants in DCI format 0_0 and DCI format 0_1 may be different. For example, in order of prioritized use of the uplink grant, DCI format 0_c may have the highest priority, DCI format 0_0 may have the second highest priority, and DCI format 0_1 may have the lowest priority. As the payload size of the DCI format decreases, the priority may be higher. Here, among the uplink grants overlapping in the time domain, only an uplink grant having a higher priority may be used. In the prioritizing, hereinafter, only the highest prioritized uplink grant may be used, or only multiple uplink grants having higher priorities may be used.

Note that the present embodiment describes the case of one serving cell (one component carrier), but may also be applied to carrier aggregation. In the case of the carrier aggregation, in addition to the priority of the DCI format described above, the priority may vary depending on the type of the serving cell in which the DCI format is detected. For example, in a case that the DCI formats having the same priority are detected in multiple serving cells and multiple uplink grants overlap in the time domain, the uplink grant in the DCI format detected in the Pcell may have the highest priority, the uplink grant in the DCI format detected in the PScell may have the second highest priority, and the uplink grant in the DCI format detected in the Scell may have a lower priority. In a case of Dual Connectivity (DC), an uplink grant in the DCI format detected in a PCG serving cell may be prioritized over an uplink grant in the DCI format detected in a SCG serving cell. In a case that the SUL is available, an uplink grant in the DCI format detected in SUL carrier may be prioritized over an uplink grant in the DCI format detected in non-SUL carrier. The SUL uses a low frequency, and thus, has a wide coverage and is likely to satisfy the requirements of high reliability and low latency. The present embodiment may also apply in a case that a BWP is configured, and an uplink grant in the DCI format detected in the BWP having a wider subcarrier spacing may be prioritized over an uplink grant in the DCI format detected in the BWP having a narrower subcarrier spacing.

Note that the present embodiment describes mainly the uplink grant, but may be applied to the downlink grant for the SPS and the C-RNTI.

In the present embodiment, the priority in the case that multiple uplink grants overlap in the time domain is determined depending on whether the uplink grant is notified using the DCI format satisfying the high reliability. As a result, the base station apparatus can configure the uplink data transmission to be prioritized by differently using the DCI formats for notifying the uplink grant. As a result, the requirements of data requiring high reliability and low latency can be satisfied.

Second Embodiment

The present embodiment describes a method for determining a priority in a case that multiple uplink grants overlap in the time domain in a case that the SPS/grant free access Type 1 without activation using the DCI format is used, in order to achieve high reliability. A communication system according to the present embodiment includes the base station apparatus 10 and the terminal apparatus 20 illustrated in FIG. 3, FIG. 4, FIG. 5, and FIG. 6. Differences from/additions to the first embodiment will be mainly described below.

In the previous embodiment, the SPS/grant free access Type 2 is used, and the SPS-config is received through RRC signaling, and thereafter, activation is performed using the DCI format, thereby causing the configured uplink grant (periodic radio resource) to be available. On the other hand, in the SPS/grant free access Type 1 according to the present embodiment, in a case that rrcConfiguredUplinkGrant, besides the SPS-config, is received through RRC signaling, the configured uplink grant (periodic radio resources) is caused to be available. Here, in a case of the Pcell, the configured uplink grant is available in a case that the SPS-config and the rrcConfiguredUplinkGrant are received, and in a case of the Scell, the configured uplink grant is caused to be available in a case that the SPS-config and the rrcConfiguredUplinkGrant are received, and that the Scell is activated. In a case that the BWP is configured, the configured uplink grant is available in a case that the SPS-config and the rrcConfiguredUplinkGrant for the active BWP are already received.

The present embodiment describes a method for determining a priority of an uplink grant in a case that the uplink grant addressed to the C-RNTI is notified using DCI format 0_0/0_1, in a case that the terminal apparatus receives the SPS-config and the rrcConfiguredUplinkGrant and the above-described configured uplink grant is available. It is known that, in a case that the configured uplink grant overlaps in the time domain with the uplink grant addressed to the C-RNTI in DCI format 0_0/0_1, the uplink grant addressed to the C-RNTI is prioritized. However, this means that even in a case that data requiring high reliability and low latency (URLLC data) is transmitted based on the configured uplink grant of the SPS/grant free access, and data requiring relatively non-severe high reliability and low latency is transmitted based on the uplink grant addressed to the C-RNTI in DCI format 0_0/0_1, in the case that the configured uplink grant overlaps in the time domain with the uplink grant addressed to the C-RNTI in DCI format 0_0/0_1, the uplink grant addressed to the C-RNTI in DCI format 0_0/0_1 is prioritized, regardless of the requirements of high reliability and low latency.

Thus, in the present embodiment, the priority is configured in a case that multiple uplink grants overlap in the time domain. In the SPS/grant free access Type 1, since there is no notification of the activation in the DCI format, the notification is given in association with information about some fields of the rrcConfiguredUplinkGrant in the RRC signaling. The rrcConfiguredUplinkGrant may include the time domain resource allocation, the time domain offset, the frequency domain resource allocation, the DMRS configuration, MCS and transport block size (mcsAndTBS), and the number of repetitive transmissions of the same data (repK).

In a case that the configured uplink grant of the SPS/grant free access Type 1 overlaps in the time domain with the uplink grant addressed to the C-RNTI in DCI format 0_0/0_1, the configured uplink grant of the SPS/grant free access Type 1 may be prioritized in a case that the following conditions are satisfied.

In a case that the time domain resource allocation is equal to or less than the prescribed number of OFDM symbols, the uplink grant may be prioritized. In a case that the starting position of the OFDM symbol used for the transmission of data included in the time domain resource allocation is smaller than a prescribed value, the uplink grant may be prioritized. The prescribed number of OFDM symbols and the prescribed value of the starting position of the OFDM symbol may be predetermined, or may be notified by way of the higher layer control information. For example, the above prescribed value and the like may be notified through RRC signaling as a field in the configuration of the SPS-config, as a field in the configuration of the rrcConfiguredUplinkGrant, or as a field in another configuration.

In a case that the time domain offset is equal to or less than a prescribed value, the uplink grant may be prioritized. The prescribed value may be predetermined, or may be notified by way of the higher layer control information. For example, the above prescribed value and the like may be notified through RRC signaling as a field in the configuration of the SPS-config, as a field in the configuration of the rrcConfiguredUplinkGrant, or as a field in another configuration. For example, a prescribed condition of the dynamic transmission power control switching indicator may be a condition where the configuration of a portion of the search space for detecting the DCI format is set up through RRC, and the DCI format is detected under the configured conditions. Specifically, the condition example includes specifying either the CSS or the USS, specifying a prescribed aggregation level (aggregation level 4 or higher, or 8 or higher), and the like. This means that a limitation is put on a case that the uplink grant is transmitted at a low coding rate by specifying a high aggregation level, and it is possible to satisfy the high reliability of the PDCCH uplink grant and the PUSCH data.

In a case that the number of resource blocks included in the frequency domain resource allocation is equal to or less than a prescribed value, the uplink grant may be prioritized. The prescribed value may be predetermined, or may be notified by way of the higher layer control information. For example, the above prescribed value and the like may be notified through RRC signaling as a field in the configuration of the SPS-config, as a field in the configuration of the rrcConfiguredUplinkGrant, or as a field in another configuration.

In a case that the DMRS configuration has a prescribed configuration, the uplink grant may be prioritized. The prescribed configuration may be predetermined, or may be notified by way of the higher layer control information. For example, the above prescribed configuration may be notified through RRC signaling as a field in the configuration of the SPS-config, as a field in the configuration of the rrcConfiguredUplinkGrant, or as a field in another configuration.

In a case that the MCS and transport block size has a prescribed configuration (e.g., a low modulation order, a low coding rate, a low frequency efficiency depending on modulation order and coding rate, and a small transport block size), the uplink grant may be prioritized. The prescribed configuration may be predetermined, or may be notified by way of the higher layer control information. For example, the above prescribed configuration may be notified through RRC signaling as a field in the configuration of the SPS-config, as a field in the configuration of the rrcConfiguredUplinkGrant, or as a field in another configuration.

In a case that the number of repetitive transmissions of the same data (repK) is greater than a prescribed value, the uplink grant may be prioritized. The prescribed value may be predetermined, or may be notified by way of the higher layer control information. For example, the above prescribed value and the like may be notified through RRC signaling as a field in the configuration of the SPS-config, as a field in the configuration of the rrcConfiguredUplinkGrant, or as a field in another configuration.

In a case that a periodicity of the SPS/grant free access is shorter than a prescribed periodicity, the uplink grant may be prioritized. The prescribed periodicity may be predetermined, or may be notified by way of the higher layer control information. For example, the above prescribed periodicity and the like may be notified through RRC signaling as a field in the configuration of the SPS-config, as a field in the configuration of the rrcConfiguredUplinkGrant, or as a field in another configuration.

In a case that the number of HARQ processes is smaller than a prescribed value, the uplink grant may be prioritized. The prescribed value may be predetermined, or may be notified by way of the higher layer control information. For example, the above prescribed value and the like may be notified through RRC signaling as a field in the configuration of the SPS-config, as a field in the configuration of the rrcConfiguredUplinkGrant, or as a field in another configuration.

In a case that the transmit power configuration (the target received power of the SPS) is greater than a prescribed value, the uplink grant may be prioritized. The prescribed value may be predetermined, or may be notified by way of the higher layer control information. For example, the above prescribed value and the like may be notified through RRC signaling as a field in the configuration of the SPS-config, as a field in the configuration of the rrcConfiguredUplinkGrant, or as a field in another configuration.

In a case that the transform precoder (TransformPrecoder) has a prescribed configuration, the uplink grant may be prioritized. The prescribed configuration may be predetermined, or may be notified by way of the higher layer control information. For example, the above prescribed configuration may be notified through RRC signaling as a field in the configuration of the SPS-config, as a field in the configuration of the rrcConfiguredUplinkGrant, or as a field in another configuration.

Note that the present embodiment describes the example in which the priority of the uplink grant is configured in association with the field in the configuration of the SPS-config or rrcConfiguredUplinkGrant. However, a field for configuring a priority may be prepared in either the SPS-config or the rrcConfiguredUplinkGrant so that the priority of the uplink grant may be determined based on the priority field. Three or more priorities may be configured.

In the present embodiment, the priority in the case that multiple uplink grants overlap in the time domain is determined in association with the configuration information about the SPS/grant free access Type 1. As a result, the base station apparatus can configure the uplink data transmission to be prioritized by differently using the configuration information of the SPS/grant free access Type 1. As a result, the data requirements requiring high reliability and low latency can be satisfied.

Third Embodiment

The present embodiment describes a method for determining a priority in the case that multiple uplink grants destined to the C-RNTI overlap in the time domain. A communication system according to the present embodiment includes the base station apparatus 10 and the terminal apparatus 20 illustrated in FIG. 3, FIG. 4, FIG. 5, and FIG. 6. Differences from/additions to the first embodiment will be mainly described below.

The present embodiment describes a method for determining a priority of an uplink grant in a case that the uplink grant addressed to the C-RNTI in DCI format 0_0/0_1 overlaps in the time domain with the uplink grant addressed to the C-RNTI in DCI format 0_c.

FIG. 9 is a diagram illustrating an example of a notification of an uplink grant according to a third embodiment. The figure illustrates an example in which the uplink grant addressed to the C-RNTI is notified in DCI format 0_0/0_1 on the PDCCH in the slot x, and is allocated in the slots x+1 to x+3. Next, in the slot x+1, an uplink grant addressed to the C-RNTI is notified in the compact DCI, and is allocated in the slot x+2. In this case, in the slot x+2, the uplink grant addressed to the C-RNTI in DCI format 0_0/0_1 overlaps in the time domain with the uplink grant addressed to the C-RNTI in the Compact DCI (overlap in at least some of the OFDM symbols). In this case, the data transmission may be performed prioritizing the configured uplink grant in the Compact DCI. This means that the configured uplink grant using the Compact DCI that satisfies high reliability is prioritized as described in the previous embodiment, regardless of the type of scheduling such as dynamic scheduling and the SPS. As described above, in a case that multiple uplink grants for the C-RNTI overlap in the time domain, the uplink grant notified using the Compact DCI may be prioritized.

Note that in the present embodiment, the priority of the uplink grant is determined depending on the DCI format, but the priority may be determined depending on the search space in which the DCI format has been detected, or the priority may be determined depending on both the DCI format and the search space. For example, the uplink grant in the DCI format detected in the common search space may be prioritized, and the uplink grant in the DCI format detected in the user-specific search space may not be prioritized.

Note that in the present embodiment, the description is given assuming that the priorities of the uplink grants in DCI format 0_0 and DCI format 0_1 are the same, but the priorities of the uplink grants in DCI format 0_0 and DCI format 0_1 may be different. For example, in order of higher priority of the uplink grant, DCI format 0_c may have the highest priority, DCI format 0_0 may have the second highest priority, and DCI format 0_1 may have the lowest priority. As the payload size of the DCI format decreases, the priority may be higher.

Note that the present embodiment describes the case of one serving cell (one component carrier), but may also be applied to carrier aggregation. In the case of the carrier aggregation, in addition to the priority of the DCI format described above, the priority may vary depending on the type of the serving cell in which the DCI format is detected. For example, in a case that the DCI format having the same priority is detected in multiple serving cells and multiple uplink grants overlap in the time domain, an uplink grant in the DCI format detected in the Pcell may be the highest prioritized, an uplink grant in the DCI format detected in the PScell is next prioritized, and the priority of an uplink grant in the DCI format detected in the Scell may be lower prioritized. In a case of Dual Connectivity (DC), an uplink grant in the DCI format detected in a PCG serving cell may be prioritized over an uplink grant in the DCI format detected in a SCG serving cell. In a case that the SUL is available, an uplink grant in the DCI format detected in SUL carrier may be prioritized over an uplink grant in the DCI format detected in non-SUL carrier. The SUL has a low frequency, and thus, has a wide coverage and is likely to satisfy the requirements of high reliability and low latency. The present embodiment may also apply in a case that the BWP is configured, and an uplink grant in the DCI format detected in a BWP having a wider subcarrier spacing may be prioritized over an uplink grant in the DCI format detected in a BWP having a narrower subcarrier spacing.

Note that the present embodiment describes mainly the uplink grant, but may be applied to the downlink grant for the C-RNTI.

In the present embodiment, the priority in the case that multiple uplink grants overlap in the time domain is determined depending on whether or not the uplink grant is notified using the DCI format satisfying the high reliability. As a result, the base station apparatus can configure the uplink data transmission to be prioritized by differently using the DCI formats for notifying the uplink grant. As a result, the data requirements requiring high reliability and low latency can be satisfied.

In all of the first to third embodiments, an uplink grant to be prioritized and an uplink grant not to be prioritized are present. The data transmission based on the uplink grant not to be prioritized may be performed using the OFDM symbols not used for the uplink grant to be prioritized in the slot used for the data transmission based on the uplink grant to be prioritized. In addition, the data transmission based on the uplink grant not to be prioritized may be performed in a case that the number of OFDM symbols not used for the uplink grant to be prioritized in the slot used for the data transmission based on the uplink grant to be prioritized is equal to or more than a prescribed value, and may be dropped in a case that the relevant number of OFDM symbols is less than the prescribed value. The prescribed value may be predetermined, or may be notified by way of the higher layer control signal (RRC signaling). Whether to perform the data transmission based on the uplink grant not to be prioritized may be determined depending on whether a prescribed coding rate is satisfied. For example, in a case that the coding rate exceeds one, the data transmission may not be performed, or may be interrupted. In a case that after the data transmission base on the uplink grant not to be prioritized starts, a notification of overlapping in the time domain with the prioritized uplink grant is received, it may be determined whether the transmission is interrupted or the data transmission is continued using the OFDM symbols except for those not used for the uplink grant to be prioritized, depending on whether the prescribed number of OFDM symbols or the prescribed coding rate is satisfied. Here, the uplink grant to be prioritized may be notified in the DCI format using the OFDM symbol in the center of the slot (for example, the seventh OFDM symbol and the eighth OFDM symbol) rather than the OFDM symbol at the beginning of the slot.

Note that the embodiments herein may be applied in combination with multiple embodiments, or each embodiment only may be applied.

A program running on an apparatus according to the present invention may serve as a program that controls a Central Processing Unit (CPU) and the like to cause a computer to operate in such a manner as to realize the functions of the above-described embodiment according to the present invention. Programs or the information handled by the programs are temporarily read into a volatile memory, such as a Random Access Memory (RAM) while being processed, or stored in a non-volatile memory, such as a flash memory, or a Hard Disk Drive (HDD), and then read by the CPU to be modified or rewritten, as necessary.

Note that the apparatuses in the above-described embodiments may be partially enabled by a computer. In that case, a program for realizing the functions of the embodiments may be recorded on a computer readable recording medium. This configuration may be realized by causing a computer system to read the program recorded on the recording medium for execution. It is assumed that the “computer system” refers to a computer system built into the apparatuses, and the computer system includes an operating system and hardware components such as a peripheral device. Furthermore, the “computer-readable recording medium” may be any of a semiconductor recording medium, an optical recording medium, a magnetic recording medium, and the like.

Moreover, the “computer-readable recording medium” may include a medium that dynamically retains a program for a short period of time, such as a communication line that is used for transmission of the program over a network such as the Internet or over a communication line such as a telephone line, and may also include a medium that retains a program for a fixed period of time, such as a volatile memory within the computer system for functioning as a server or a client in such a case. Furthermore, the above-described program may be one for realizing some of the above-described functions, and also may be one capable of realizing the above-described functions in combination with a program already recorded in a computer system.

Furthermore, each functional block or various characteristics of the apparatuses used in the above-described embodiments may be implemented or performed on an electric circuit, that is, typically an integrated circuit or multiple integrated circuits. An electric circuit designed to perform the functions described in the present specification may include a general-purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), or other programmable logic devices, discrete gates or transistor logic, discrete hardware components, or a combination thereof. The general-purpose processor may be a microprocessor or may be a processor of known type, a controller, a micro-controller, or a state machine instead. The above-mentioned electric circuit may include a digital circuit, or may include an analog circuit. Furthermore, in a case that with advances in semiconductor technology, a circuit integration technology appears that replaces the present integrated circuits, it is also possible to use an integrated circuit based on the technology.

Note that the invention of the present patent application is not limited to the above-described embodiments. In the embodiment, apparatuses have been described as an example, but the invention of the present application is not limited to these apparatuses, and is applicable to a terminal apparatus or a communication apparatus of a fixed-type or a stationary-type electronic apparatus installed indoors or outdoors, for example, an AV apparatus, a kitchen apparatus, a cleaning or washing machine, an air-conditioning apparatus, office equipment, a vending machine, and other household apparatuses.

The embodiments of the present invention have been described in detail above referring to the drawings, but the specific configuration is not limited to the embodiments and includes, for example, an amendment to a design that falls within the scope that does not depart from the gist of the present invention. Various modifications are possible within the scope of the present invention defined by claims, and embodiments that are made by suitably combining technical means disclosed according to the different embodiments are also included in the technical scope of the present invention. Furthermore, a configuration in which constituent elements, described in the respective embodiments and having mutually the same effects, are substituted for one another is also included in the technical scope of the present invention.

INDUSTRIAL APPLICABILITY

The present invention can be preferably used in a base station apparatus, a terminal apparatus, and a communication method. 

What is claimed is:
 1. A terminal apparatus for communicating with a base station apparatus, the terminal apparatus comprising: a receiver configured to detect a first Downlink Control Information (DCI) format, a second DCI format, and Radio Resource Control (RRC) information; and a transmitter configured to perform data transmission based on any of a first uplink grant which is a configured uplink grant to be available after activation of a periodic radio resource by using a radio resource periodicity included in the RRC information and the first DCI format, a second uplink grant which is a configured uplink grant to be available after activation of the periodic radio resource by using the radio resource periodicity included in the RRC information and the second DCI format, and a third uplink grant using an uplink grant addressed to a Cell-Radio Network Temporary Identifier (C-RNTI) to be available after detection of allocation information of an aperiodic radio resource included in the second DCI format, wherein: the receiver is further configured to detect at least two of the first DCI format for the first uplink grant, the second DCI format for the second uplink grant, and the second DCI format for the third uplink grant, and the transmitter is further configured to override, in a case that the uplink grant addressed to the C-RNTI of the third uplink grant overlaps in time domain with the configured uplink grant of the second uplink grant, the configured uplink grant of the second uplink grant, and to override, in a case that the configured uplink grant of the first uplink grant overlaps in the time domain with the uplink grant addressed to the C-RNTI of the third uplink grant, the uplink grant addressed to the C-RNTI of the third uplink grant.
 2. The terminal apparatus according to claim 1, wherein: data transmission of a fourth uplink grant is enabled, the fourth uplink grant using an uplink grant addressed to a second C-RNTI to be available after detection of allocation information of an aperiodic radio resource included in the first DCI format, the receiver is further configured to detect the first DCI format for the first uplink grant and the first DCI format for the fourth uplink grant, and the transmitter is further configured to override, in a case that the uplink grant addressed to the second C-RNTI of the fourth uplink grant overlaps in a time domain with the configured uplink grant of the first uplink grant, the configured uplink grant of the first uplink grant.
 3. The terminal apparatus according to claim 1, wherein: the transmitter is further configured to perform data transmission of a fifth uplink grant which is a configured uplink grant with the RRC information including allocation information of a radio resource for the data transmission, without receiving the first DCI format and the second DCI format, and the transmitter is further configured to determine, in a case that the uplink grant addressed to the C-RNTI of the third uplink grant overlaps in time domain with the configured uplink grant of the fifth uplink grant, which of the third uplink grant and the fifth uplink grant is to be used at least in an overlapping Orthogonal Frequency Division Multiplexing (OFDM) symbol, based on at least one piece of information among resource allocation in the time domain, a second radio resource periodicity, and an offset in the time domain, each of which is included in the RRC information for the fifth uplink grant.
 4. The terminal apparatus according to claim 1, wherein the configured uplink grant of the first uplink grant overlapping in time domain with the uplink grant addressed to the C-RNTI of the third uplink grant corresponds to OFDM symbols to be used for data transmission based on the first uplink grant and OFDM symbols to be used for data transmission based on the third uplink grant being at least partially overlapping each other.
 5. The terminal apparatus according to claim 1, wherein a number of bits in a Modulation and Coding Scheme (MCS) field included in the first DCI format is smaller than a number of bits in an MCS field included in the second DCI format. 